Fuel math gets expensive when the numbers answer different questions.

Last month closes clean. Fuel dollars match the miles. The cost-per-mile record is real. Then diesel moves and the next load gets priced with the old fuel line because, technically, nothing in the record is wrong.

That is the trap. A historical record can be perfectly accurate and still be stale for a forward-looking decision. Your old fuel number is not lying. It is simply describing a month that already left the building.

Keep the record. Reprice the decision.

The completed Fuel Cost Record belongs to the period that produced it. Do not overwrite it because today’s price changed. That would turn an Actual Record into a moving estimate and destroy the trail you may need later.

For a current planning check, keep only three inputs together: the miles you are pricing, a supportable current net diesel price you can actually buy at, and the MPG basis you are deliberately using for the estimate. If the MPG is not established, leave it Unknown. If the current price is only a public benchmark, label it as a benchmark rather than pretending it is your card price.

EIA’s weekly on-highway diesel series is useful market context, but EIA’s own methodology says the survey is a volume-weighted estimate of cash, self-serve pump prices from a sample of outlets. That is not the same thing as the net price on your account after a card discount, rebate, or fee.

Watch $84.62 appear without changing a single mile

This is a transparent planning example, not a market forecast and not an operator record.

Assume the truck is planning 1,000 miles. The saved fuel record used $3.70 per gallon. For the new planning check, the operator enters a current net price of $4.25 per gallon. The MPG basis used for both views is 6.5 MPG.

1,000 miles ÷ 6.5 MPG = 153.846 gallons

Old planning view:
153.846 × $3.70 = $569.23

Current entered-price view:
153.846 × $4.25 = $653.85

Difference:
$653.85 − $569.23 = $84.62 per 1,000 miles

The current-price view is $84.62 higher per 1,000 planned miles under those entered assumptions. That does not prove the next load will consume exactly 153.846 gallons, and it does not revise the historical record. It shows how much the planning fuel line changed because the entered fuel price changed.

On 2,500 planned miles with the same inputs, the price difference alone would scale to about $211.54. Again: planning arithmetic, not a promise from the truck.

Do not fix a stale price with a fake MPG

This is where a useful update can become a bad number. Purchased gallons over an arbitrary period are not automatically gallons consumed during that period. Beginning and ending tank inventory can move fuel across the date boundary. If your MPG basis is only a remembered dashboard number, label it as a User Estimate. Do not polish it into an Actual Record because the formula has decimals.

The same discipline applies to the current fuel price. A national or regional average can show direction. An app price can support a stop estimate if it is current and account-specific. A final receipt or statement records the actual transaction. They are different evidence states with different jobs.

When does this check matter?

Use it when the saved fuel record is old enough that a meaningful price move could change a rate floor, cash requirement, or load decision. There is no universal “refresh after X days” rule here. The trigger is the decision: if the historical fuel line could materially change what you are about to quote or accept, run the current-price view.

If the new view barely moves the economics, keep working. A check that says “nothing important changed” did its job. HSHQ does not need to manufacture a crisis just because diesel has a talent for getting everyone’s attention.

Put the reprice next to the quote, not inside the history

If the current planning view changes the load economics enough to matter, keep the two fuel views side by side: “completed-period fuel basis” and “current entered fuel basis.” That lets you explain exactly why the rate floor moved without pretending the old record was wrong.

It also gives you a clean reversal test. If the current entered fuel price falls back toward the historical level, rerun the planning view. The historical record stays untouched; only the planning assumption moves. That is the whole point of keeping a ledger separate from a forecast.

For a small fleet, do the same by unit when the fuel behavior differs materially. A fleet average can be useful for a fleet decision, but it should not quietly become the planning fuel line for a truck that runs a different lane, trailer, or operating pattern.

The carrier hands you a fuel card. The app shows a discount. The settlement deducts fuel. A fuel-surcharge line appears somewhere else. By Friday, four fuel numbers are sitting on the same page looking like cousins.

Do not assume they are the same money.

For an owner-operator leased to an authorized carrier, the useful question is not “Does the carrier have a fuel program?” It is: What do the written lease and settlement say happens to the fuel price, the card fees, the fuel deduction, and any fuel-related compensation?

The lease has to do more than wave at the subject

49 CFR 376.12 requires, among other things, that the lease clearly state compensation and specify which party is responsible for fuel and fuel taxes. It also requires charge-back items to be identified, including how those amounts are computed, with supporting documents available to the lessor. The regulation does not say that every carrier must pass through a particular fuel-card discount or a particular fuel-surcharge formula.

That distinction matters. “The carrier gets a discount” is not the same statement as “my lease says I receive that discount.” “The customer pays a surcharge” is not automatically the same as “my compensation includes 100% of that surcharge.” Read the actual compensation language before turning a suspicion into a conclusion.

One fill, $10.40 apart

Use a same-fill comparison. This example is deliberately simple and uses entered terms, not a claim about any real carrier or card.

The truck plans to buy 120 gallons.

Carrier program: net fuel price shown for the account is $3.64 per gallon, plus a $2.00 transaction charge that is passed through on the settlement.

Owner’s separate card: current net price at a practical stop is $3.57 per gallon, with no entered transaction fee for this fill.

Carrier program:
120 × $3.64 = $436.80
$436.80 + $2.00 fee = $438.80

Owner card:
120 × $3.57 = $428.40

Difference:
$438.80 − $428.40 = $10.40

On those entered terms, the owner’s card is $10.40 cheaper for this 120-gallon fill. That is a transaction result, not a verdict on the whole carrier program. The carrier card might have better network fit, easier settlement accounting, different credit timing, or other written terms that matter. Put those beside the dollars rather than hiding them inside the word “convenience.”

Now trace the surcharge separately

Suppose the written compensation term says the owner receives 42 cents per eligible loaded mile as fuel-related compensation, and the load has 800 eligible loaded miles.

$0.42 × 800 eligible loaded miles = $336.00

If the settlement shows $310.00 on the corresponding line, the documented difference is $26.00 for review. It is not automatically “$26 stolen,” “$26 legally owed,” or proof of a violation. First confirm that the same mileage definition, load, adjustment, and compensation term apply.

This is where settlement arguments often get muddy: the driver compares the $336 contractual calculation with the pump receipt, while the carrier may be using a separate compensation formula. Pump economics and compensation can both matter, but they answer different questions.

Four lines worth checking

Pull the lease, the fuel-card terms that apply to your account, the fuel transaction, and the settlement. Then answer four plain questions:

• Who is responsible for buying fuel and fuel taxes?
• If the carrier’s card is used, what exact fuel amount and fees can be deducted?
• Does the lease or attached compensation schedule say anything about fuel discounts, rebates, or surcharge pass-through?
• Can the settlement be traced back to the written calculation and supporting documents?

If one of those answers is missing, do not replace it with what another carrier does. Another carrier’s lease is excellent evidence of another carrier’s lease.

Do not let settlement convenience hide the per-gallon result

A carrier card may make accounting easier because fuel deductions appear directly on the settlement. Convenience is real, but it still needs a price tag. Convert the carrier-card result and your alternative into the same fill or monthly basis, then show the dollar difference separately from the paperwork advantage.

If the carrier program is $10.40 more expensive on this fill but saves administrative time or provides a cash-timing benefit, write those benefits down as separate decision factors. Do not erase the $10.40 by calling the program “easier.” And do not ignore a useful settlement workflow just because another card wins one fill.

The point is to make the tradeoff visible enough that nobody has to argue from memory at the end of the week.

A fuel surcharge matters most when the same lane, customer, or contract keeps using it. On a one-off load, you may check it once and move on. On a six-month lane, a small repeatable mismatch can become real money simply because the same arithmetic keeps showing up.

Start with the written formula. Not the pump receipt. Not the national average you wish the contract had used. Not the number somebody remembers from last Tuesday.

EIA publishes diesel-price data, but EIA explicitly says it does not calculate, assess, or regulate a universal diesel fuel surcharge. The surcharge method is privately negotiated. That means the agreement has the steering wheel.

A surcharge formula is arithmetic with a contract attached

Look for the exact index, the applicable index date, base fuel price, contract MPG if one is specified, eligible mileage definition, caps, floors, tables, percentages, and rounding instructions. “EIA price” is not specific enough when the contract names a national series, a regional series, or a particular publication date.

Likewise, “miles” can mean loaded, dispatched, practical, actual, or something else. A formula can be calculated perfectly and still be wrong because the wrong miles were invited into it.

The $420 load

This is a transparent calculation with fictional contract inputs. It is not a model contract and not a claim about what any carrier should pay.

Assume the written term says:

(named diesel index − base price) ÷ contract MPG × eligible loaded miles

The written inputs for this load are:

• named diesel index: $4.05 per gallon;
• base fuel price: $1.25 per gallon;
• contract MPG: 6.0;
• eligible loaded miles: 900.

$4.05 − $1.25 = $2.80 per gallon

$2.80 ÷ 6.0 MPG = $0.466666... per eligible mile

$0.466666... × 900 miles = $420.00

The formula produces $420.00. Keep the repeating per-mile value at full precision until the final multiplication; rounding it to $0.467 too early would create a small artificial difference.

If the invoice and settlement both show $420.00, the written formula and those documents match on this load. That does not prove the load was profitable or that $420 covered actual fuel expense. It proves the surcharge trace matched.

Do not jump from “$700 mismatch” to “$700 legally owed.” First confirm all twenty loads used the same written terms, index dates, eligible mileage basis, and settlement treatment. One changed rate confirmation can break the pattern.

Pump cost is useful, but it is a different argument

Suppose the truck actually spent more than $420 worth of fuel on the load. That may tell you the contract’s recovery does not cover the operation’s real fuel burden. Useful pricing information. It does not automatically mean the contract calculation was wrong.

The reverse is also possible. The formula may pay more than the load’s incremental fuel cost under your operating conditions. That does not turn the extra recovery into an IFTA credit or change the written formula retroactively.

Keep three records separate: what the truck paid for fuel, what the freight agreement promised as recovery, and what the quarter’s IFTA record does with jurisdiction miles and tax-paid gallons.

Where to stop

If the agreement does not establish the index date, mileage basis, or another required input, the trace is Not Ready. Choosing the value that produces the answer you expected is not reconciliation. It is fan fiction with a calculator.

For a repeat lane, save the written term, each recalculation, the corresponding invoice, the settlement, and any deduction detail. The useful pattern is not “I think they shorted me.” It is “Here is the written formula, here is the supported result, here is the settlement, and here is the first point they separate.”

Build a lane file before the fifth argument, not after it

For recurring freight, save one clean copy of the controlling surcharge term and record the inputs that can legitimately change: index date, index value, eligible miles, or another stated variable. Then each load becomes a trace, not a new interpretation of the contract.

If the agreement changes, start a new version with an effective date. Do not let the newest rate confirmation silently rewrite the first three months of the lane. A contract history is boring right up until two people remember two different versions.

This is also where a repeated small discrepancy becomes easier to prove. The useful evidence is not a screenshot of one odd settlement. It is a sequence showing the same written rule, the supported calculation, the paid amount, and the date the pattern changed.

The truck stop sign says $3.79. The app says $3.61. The receipt agrees with the app. Two days later the statement posts a $4 rebate and a separate $1 fee.

Congratulations: one fill now has four perfectly respectable numbers and only one completed fuel record.

The trick is not choosing the number you like best. The trick is giving each number one job.

The roadside sign gets the billboard. The statement gets the last word.

A posted cash or credit price tells you what the location is offering under that payment basis at that moment. An app price can support a pre-purchase decision when the location, fuel type, timestamp, account eligibility, and pricing basis are clear. A receipt records the pump transaction. A final statement can settle a rebate, adjustment, reversal, or separate account fee after the nozzle is already back in the cradle.

EIA’s weekly public diesel estimate belongs even farther away from the transaction record. EIA collects cash self-serve pump prices from a sample of outlets and publishes volume-weighted national and regional estimates. Useful market context. It is not evidence that your account bought fuel for that price.

Follow one 100-gallon fill to the end

This example uses stated assumptions only.

• posted credit price: $3.79 per gallon;
• current app/account price: $3.61 per gallon;
• receipt: 100 gallons at $3.61 = $361.00;
• separate card transaction fee: $1.00;
• final diesel rebate tied to the fill: $4.00.

The cash movement at the time of settlement is:

$361.00 fuel transaction + $1.00 separate fee = $362.00

Once the $4.00 rebate is final and attributable to this fuel purchase, the completed diesel purchase amount for the fuel record becomes:

$361.00 − $4.00 rebate = $357.00

$357.00 ÷ 100 gallons = $3.57 per gallon

The final diesel purchase price is $3.57 per gallon. The separately itemized $1.00 card fee remains visible for provider economics rather than being quietly buried in the diesel-purchase field. If your own bookkeeping system uses a broader all-in card-cost category, label that different basis clearly.

A pending rebate is not a completed rebate

If the provider says a credit should arrive next week, do not record it as if it already did. Preserve the current final amount and the pending benefit separately. When the statement settles, update the completed transaction record with the supported credit.

The same rule works in reverse for reversals and corrections. If the app showed a discount that never survived the statement, the app supported a buying estimate; it did not become permanent truth through good intentions.

Cost per mile needs matching dates, not just correct dollars

Now suppose a 30-day record shows $4,760 of final diesel purchase cost and 12,200 operating miles for the same truck and the same completed dates.

$4,760 ÷ 12,200 operating miles = $0.3902 per mile

That is about 39.0 cents per operating mile for that matched fuel-purchase record.

If the $4,760 covers two trucks while the 12,200 miles cover one, the division is not “conservative.” It is broken. If the dollars cover 30 days and the miles cover 31, the denominator has wandered off.

Purchased gallons also do not automatically establish MPG. Tank inventory can move fuel across period boundaries. A neat fuel card export is still not permission to invent consumption.

What to keep

For each included purchase, keep date, location, fuel type, gallons, final diesel amount, discounts or rebates that actually settled, and separate non-fuel fees. Then match the fuel dollars to operating miles from the same period and vehicle scope.

If a transaction is unsettled, the rebate is pending, or the period does not match, the honest result is Not Ready. The calculator will survive the disappointment.

One more trap: rewards that never become money

Points, loyalty credits, and rebates can have value, but only when the value and redemption are supportable. A balance that expires unused is not fuel savings. It is a very decorative number in an app.

If a reward has a reliable cash-equivalent value and you actually receive it, show it separately so the reader can see both the pump transaction and the later benefit. If redemption depends on future purchases, brand-specific merchandise, or a threshold you may never hit, do not force it into the net fuel price as if it were cash already in the account.

That separation also makes comparisons cleaner. Two cards can both advertise “rewards” while delivering completely different timing, restrictions, and usable value.

The fuel number looks worse. Maybe the truck is sick. Maybe the route changed. Maybe idle time climbed. Maybe the “MPG” calculation quietly compared two periods with different tank levels.

All four can produce an ugly number. Only one of them is permission to start buying parts.

Before the parts cannon comes out, make sure the fuel-use drop exists outside the spreadsheet.

First question: did you actually measure fuel consumed?

A fuel-card statement tells you what was purchased. It does not automatically tell you what the truck consumed during the same dates. If Period A starts with full tanks and ends nearly empty while Period B starts and ends full, dividing purchases by miles creates two different inventory treatments and calls them MPG.

Use a consistent consumption method. A full-to-full record can work when the tank state is made comparable and the distance between fills is meaningful. A validated vehicle fuel-used record may also support the check. What does not work is taking an arbitrary month of purchases, assuming every gallon was burned inside that month, and then diagnosing the truck from the answer.

Fifteen extra gallons per 1,000 miles

This example uses matched, measured consumption. It is an illustration, not a normal MPG claim.

Period A: 1,000 miles and 160 gallons consumed.

1,000 ÷ 160 = 6.25 MPG

Period B: 1,000 miles and 175 gallons consumed.

1,000 ÷ 175 = 5.71 MPG

For the same 1,000 miles, Period B used 15 additional gallons. At an entered fuel price of $4.00 per gallon, that difference is:

15 gallons × $4.00 = $60.00 more per 1,000 miles

Now the problem has a dollar size: $60 per 1,000 miles under the entered price. That still does not identify the cause.

Separate the operating changes before the mechanical ones

EPA SmartWay materials identify multiple fuel-use influences and efficiency strategies, including idling, tires, aerodynamics, and operating practices. That is the useful lesson here: a change in fuel use is a symptom, not a parts order.

Compare the two periods for things that actually changed. Was there more long-duration idling? A different lane mix? More stop-and-go work? Heavier or less aerodynamic loads? Lower tire pressure? More high-speed operation? A seasonal HVAC load? A change in trailer or equipment configuration?

You do not need to prove every variable before acting. You do need enough separation to avoid blaming the engine for a route change.

Then look for a mechanical signal that has company

If the measured fuel-use deterioration persists after the obvious operating differences are accounted for, move the question to Equipment. A fuel-use change alone is not a diagnosis. Pair it with actual truck evidence: fault codes, smoke, power change, regeneration behavior, tire condition, alignment evidence, boost behavior, maintenance history, or whatever symptom belongs to the vehicle.

The useful sentence is not “My MPG is bad, therefore injectors.” It is “Measured consumption worsened by 15 gallons per 1,000 miles across comparable work, and these other symptoms appeared at the same time.” Manny can work with that. A guess wearing a calculator is still a guess.

Do not let one bad week become a trend by punctuation

A single period can be real and still be unrepresentative. Weather, congestion, a different customer, an unusual idle event, or a short measurement window can move the result. Compare enough matched work to decide whether the change persists.

There is no universal HSHQ threshold that says “a drop of X MPG means repair.” The right threshold depends on the quality of the measurement and the operating change around it. If the evidence is thin, keep the state at Watch or Not Ready rather than inventing urgency.

Make the next test cheap enough to repeat

The first useful follow-up is often not a shop visit. It is another clean measurement under comparable work. If the next matched period returns near the earlier fuel-use level, the first drop may have been operating noise. If the gap persists, the evidence for a deeper inspection gets stronger.

Keep the comparison simple enough that you can repeat it: same measurement method, similar distance, known tank-state treatment, and notes on the operating changes that obviously matter. Do not create a 27-column science project the driver will abandon after Tuesday.

When the number is repeatable, the Equipment conversation improves too. “It feels like it’s burning more fuel” becomes “three comparable records show an extra 13–16 gallons per 1,000 miles.” That is a symptom worth investigating.

“I idle a lot, so I need an APU” sounds sensible right up until the installed price meets the truck’s actual idle hours.

Idle reduction can save fuel. That part is not controversial. The buying decision is harder: how many hours are you really replacing, what does the main engine burn at idle, what does the alternative use, what is the installed cost, and what maintenance will it add?

An APU does not become a bargain because it has a tiny engine and a financing button.

Start with your hours, not somebody else’s payback story

The U.S. Department of Energy / Alternative Fuels Data Center publishes heavy-duty idle-reduction resources. Its 2015 long-haul fact sheet used about 0.8 gallon per hour as a main-engine idling assumption and showed a broader idling range of 0.6–1.5 gallons per hour. The same fact sheet used roughly 0.3 gallon per hour for a diesel APU in its worked economics.

Those are planning benchmarks from that source, not measurements of your truck or your APU. If you have a supportable measured rate, use it. If not, keep the source and date attached to the benchmark.

AFDC’s current guidance makes the bigger point: cost-effectiveness depends on the amount of idling being displaced, climate, services required, equipment cost, and the available alternatives. There is no one best technology for every truck.

A $10,000 APU at 1,200 idle hours

This is a transparent fuel-only example. The equipment cost is operator-entered for the illustration. It is not a current market average.

• idle hours being replaced: 1,200 per year;
• main-engine planning rate: 0.8 gal/hr;
• APU planning rate: 0.3 gal/hr;
• entered diesel price: $4.20/gal;
• entered installed APU cost: $10,000;
• APU maintenance: Unknown and therefore not silently set to zero.

Main engine:
1,200 × 0.8 = 960 gallons
960 × $4.20 = $4,032 per year

APU:
1,200 × 0.3 = 360 gallons
360 × $4.20 = $1,512 per year

Fuel-only difference:
$4,032 − $1,512 = $2,520 per year

Under those entered assumptions, the APU reduces fuel cost by $2,520 per year.

$10,000 installed cost ÷ $2,520 annual fuel savings = 3.97 years

The simple fuel-only payback is about 4.0 years before APU maintenance, financing, downtime, repair cost, resale effect, or any other benefit is included.

Sometimes the cheaper machine is the one you do not need

If the real need is heat, a diesel-fired bunk heater may solve a narrower job with far less fuel use than main-engine idling. DOE’s 2015 fact sheet listed a 0.04–0.08 gal/hr range for heaters. If cooling and electrical power are required, that comparison changes. Automatic stop-start, battery cooling, electrified parking, and other systems solve different combinations of needs.

Do not force every truck into an APU-vs-idle contest. Write down the services you actually need: heat, cooling, hotel power, battery support, engine warmth, or some combination. Then compare equipment that performs the same job.

Maintenance is not zero because the field is inconvenient

An APU has its own fluids, filters, belts, electrical system, cooling components, and repair risk. If you do not have a supportable annual maintenance figure, label it Unknown. You may show a fuel-only payback, but you may not quietly call it total payback.

The same applies to financing. A monthly payment is not the purchase cost, and an attractive payback does not prove the cash timing works this month.

Three perfectly respectable answers

Leave it alone: idle hours are low enough that the installed equipment does not earn its price on the entered basis.

Cheaper fix first: the truck mainly needs one service, such as bunk heat, and a narrower solution deserves comparison.

APU worth pricing: replaceable idle hours are high enough that the fuel-only economics justify getting real installed quotes and maintenance terms.

That is a better decision than “APUs save fuel.” Of course they can. The useful question is how many of your dollars they save before the warranty pamphlet starts feeling emotionally persuasive.

Separate comfort value from fuel payback

An APU can provide air conditioning, heat, electrical power, battery support, and quieter rest. Those benefits can matter even when the fuel-only payback is slow. But if comfort value is part of the buying decision, say so instead of smuggling it into the fuel calculation.

The clean record can show two conclusions at once: “fuel-only payback is 4.0 years before maintenance” and “the operator still values engine-off cooling enough to price the equipment.” That is a legitimate decision. The spreadsheet does not have to pretend every benefit is a diesel gallon.

The opposite is legitimate too. If the truck rarely idles and the operator already has workable heat or cooling, “leave it alone” may be the best answer. Not buying equipment is allowed to save 100% of its purchase price.

The alternate stop is 15 cents cheaper. That sounds like the end of the discussion.

It is the beginning.

A lower pump price still has to pay for the road required to reach it. Added miles burn fuel. A transaction fee can nibble at the difference. Time may matter when it has an actual operating value or threatens the plan.

The pump sign gets to advertise the discount. Your bank account has to survive the detour.

Count the route the truck actually adds

Use extra round-trip miles: route with the alternate stop minus the route the truck would otherwise run. “Six miles away” can become twelve extra miles when the truck must leave the route and come back. Straight-line distance is not a truck route, and the outbound leg does not get to forget its return trip.

Then use a supportable MPG basis for the planning calculation. If the MPG is uncertain, keep it labeled as a User Estimate. Do not manufacture Actual MPG from an arbitrary block of fuel purchases.

The $16.50 discount that loses 72 cents

This is a transparent decision example, not a recommendation for any stop.

• planned purchase: 110 gallons;
• on-route usable price: $3.79/gal;
• alternate usable price: $3.64/gal;
• extra round-trip distance: 12 miles;
• entered MPG: 6.5;
• alternate transaction fee: $1.50;
• operator-entered time value: $30/hour;
• extra time in the first scenario: 18 minutes.

Start with the billboard number:

110 × ($3.79 − $3.64) = $16.50 gross pump savings

Now send the detour its invoice:

12 miles ÷ 6.5 MPG = 1.846 gallons

1.846 × $3.64 = $6.72 detour fuel cost

Before time and fees, the alternate is still $9.78 cheaper.

The operator has chosen to value the 18 extra minutes at $30 per hour:

18 ÷ 60 × $30 = $9.00 time cost

Add the $1.50 transaction fee:

$16.50 − $6.72 − $9.00 − $1.50 = −$0.72

Do not invent time cost just to make the calculator look complete

If time has no supportable dollar value for this decision, do not pull an hourly rate from the air. You can show the fuel-and-fee result and keep time as an explicit unresolved factor.

But do not ignore a real time constraint either. If the detour threatens an appointment, legal driving window, parking plan, pickup, or delivery, the constraint is real even if you do not convert it to dollars.

At 30 extra minutes using the same entered $30/hour value, the time cost becomes $15.00. With the same fuel cost and fee, the alternate becomes $6.72 more expensive than the on-route stop.

Want the break-even price difference? Divide the detour by the gallons.

Using the 18-minute scenario above, total incremental detour cost is:

$6.72 fuel + $9.00 time + $1.50 fee = $17.22

Spread that across 110 planned gallons:

$17.22 ÷ 110 = $0.1565 per gallon

The alternate must be about 15.7 cents per gallon cheaper just to break even on those entered costs. Its actual advantage is only 15 cents. That is why it loses by 72 cents.

Change the gallons and the threshold changes. Change the added miles and it changes. Change the fee or the time treatment and it changes. There is no universal “ten cents cheaper is worth the detour” rule.

Fuel-only CPM and all-mile CPM are not ingredients for the same soup

If you use a broader all-mile operating cost to price the added miles, make sure fuel is already inside that CPM before adding separate detour fuel again. Counting both is not conservative. It is double billing your own truck.

Use one declared basis, show the assumptions, and let the result be boring if it is boring. Sometimes the on-route stop is $3.00 more and still wins. The truck does not require a dramatic ending.

Check the receipt afterward; the estimate is allowed to lose

After the fill, compare the estimated stop price, gallons, fee, and route with what actually happened. If the alternate authorized at a different price or the detour took longer, keep the Actual Record. The pre-trip calculation was a decision aid, not a prophecy.

Over time, those after-the-fact checks tell you whether your planning inputs are useful. If the same type of detour repeatedly takes 25 minutes instead of the entered 10, the lesson is not to blame the calculator. Update the assumption.

This is how a simple stop decision gets better without turning into route-optimization software: compare, drive, record, correct. The truck supplies enough reality on its own.

You find cheaper fuel across the state line, make a perfectly sensible buying decision, and still see tax due in another jurisdiction at quarter-end.

That does not mean the cheap fill was a mistake. It means retail fuel cost and IFTA are different jobs.

IFTA does not hand out loyalty points for buying fuel in the “right” state. It reconciles motor-fuel use tax using the quarter’s distance and tax-paid fuel records under the applicable rules.

Start with the fleet record, not the pump price

At a high level, the quarter’s total fleet distance and qualified propulsion-fuel volume establish fleet fuel economy for the IFTA calculation. Jurisdiction distance is then used to estimate fuel consumed in each jurisdiction. Supported tax-paid gallons purchased in that jurisdiction are compared with the estimated consumption, and the applicable official rate and surcharge treatment are applied.

The exact filing belongs to the current IFTA manuals, official rate matrix, and the operator’s base jurisdiction. HSHQ can explain the mechanism and organize an estimate. It does not turn an educational example into a filed return.

Watch 150 net gallons appear

This simplified example shows the mechanism before official rates are applied.

• quarter fleet distance: 12,000 miles;
• qualified propulsion fuel: 2,000 gallons;
• Jurisdiction A taxable distance: 3,000 miles;
• supported tax-paid fuel purchased in Jurisdiction A: 350 gallons.

First derive the fleet MPG:

12,000 miles ÷ 2,000 gallons = 6.0 MPG

Then estimate fuel consumed in Jurisdiction A:

3,000 miles ÷ 6.0 MPG = 500 gallons consumed

Compare that with supported tax-paid gallons:

500 consumed − 350 tax-paid = 150 net gallons

So should you buy expensive fuel just to chase an IFTA credit?

Not from this calculation alone.

Retail price affects what fuel costs the operation. Tax-paid gallons affect the IFTA credit side of the jurisdiction calculation. Those two facts can point in different directions.

A higher-tax purchase can create more tax-paid credit and still be a bad total buying decision if the fuel price and route cost are worse. A lower-priced purchase can be a good operating decision and still leave tax due elsewhere because the truck traveled more miles there than the tax-paid purchases cover.

The useful question is not “Which state gives me the best IFTA?” It is “What is the best complete fuel-buying decision, and did I keep the records IFTA needs afterward?”

The card export is helpful. It is not the whole quarter.

A fuel-card file can give you dates, locations, gallons, and transactions. It does not prove jurisdiction distance. It may also omit purchases made another way, or combine fuel types that need separation.

Distance records and fuel records have to meet in the same quarter and fleet scope. Missing miles do not become zero because the ELD export looks professional. Missing receipts do not become tax-paid gallons because the operator remembers buying fuel there.

Use the current manuals for the current quarter

IFTA, Inc. identifies the current 2026 Articles of Agreement, Audit Manual, and Procedures Manual, updated September 21, 2026 and effective August 26, 2026. Official quarterly tax-rate downloads are published separately. Rates and jurisdiction treatment are time-sensitive, so use the set that belongs to the reporting quarter.

That is also why a Guide should not hard-code a tax rate into a timeless example. The mechanism survives. The rate may not.

The clean mental model

Buying decision: What did this gallon cost after route and payment reality?

IFTA record: Where did the qualified vehicle travel, where was tax-paid propulsion fuel purchased, and what do the official quarter rules do with those records?

Keep those questions separate and IFTA becomes much less mysterious. Mix them together and the spreadsheet starts arguing with the receipt.

Why buying more fuel in a high-tax jurisdiction can fool you

It is possible to increase tax-paid gallons in a jurisdiction and improve the IFTA credit position there while still spending more money overall on the fuel purchase. That is why “buy where the tax is high” is not a complete fuel strategy.

The buying decision should compare the actual purchasable fuel price and route economics. The IFTA record should preserve the jurisdiction and tax-paid evidence from whatever purchase you make. Then the quarter-end calculation does its own job.

Think of IFTA as reconciliation after the driving and fueling happened, not a coupon program deciding where the truck should stop. The tax record follows the operation. It should not be allowed to drive the truck backward into a more expensive purchase just to make one column look better.

Quarter-end is when two exports that behaved perfectly well all month suddenly refuse to agree.

The ELD says 12,000 miles. The jurisdiction rows add to 11,720. The fuel summary says 2,000 gallons. The receipts you can actually support total 1,950. The spreadsheet is ready to calculate anyway, because spreadsheets are extremely brave when they are not the ones signing the return.

Do not reward that confidence. Reconcile the record first.

A spreadsheet can reconcile arithmetic. It cannot notarize 280 missing miles.

Start by putting a fence around the quarter: reporting dates, fleet/vehicle scope, fuel type, and the records that belong inside. Statement cycles, dispatch weeks, and delayed postings do not get to redefine the reporting period.

Then compare the whole with the parts.

The missing miles could be a state-line gap, a disabled tracking period, an omitted trip, a duplicate correction on the total, a unit-assignment problem, or a quarter-boundary issue. The Guide does not guess which. It tells you where the record broke.

Fuel gets the same treatment

Suppose the quarter summary shows 2,000 gallons but the supported qualified propulsion-fuel purchases total 1,950 gallons after duplicates, reversals, reefer fuel, and unsupported transactions are separated.

That is a 50-gallon evidence gap. Do not quietly put the 50 back because the grand total “looks right.” Find the receipt, statement, fuel-type split, or correction that supports it. If you cannot, preserve the gap.

A fuel-card export is a useful witness, not the whole case. It may not contain cash purchases, receipt images, unit detail, or the jurisdiction-distance record. Likewise, an ELD does not prove tax-paid gallons.

Only after reconciliation does the estimate deserve a rate

Once distance and fuel records reconcile, apply the official rates for the correct quarter and follow base-jurisdiction instructions. IFTA, Inc. publishes the current manuals and quarterly tax-rate matrix files. The current 2026 manuals were updated September 21, 2026 and identify the applicable procedures and agreement framework.

Do not use a current quarter’s rate just because it is the first spreadsheet you found. A tax rate with the wrong quarter is still a very official-looking wrong input.

Reserve cash without inventing tax law

Suppose the reconciled HSHQ estimate shows $620 due. The operator decides to keep an extra $100 in the account because one small documentation issue is still being resolved before filing.

Estimated amount due: $620
Operator-chosen planning buffer: $100

Cash held for the filing:
$620 + $100 = $720

The planning reserve is $720. The estimated tax remains $620. The extra $100 is a management choice, not an official IFTA requirement and not a new tax rate.

That separation matters. When HSHQ shows a reserve, the operator should be able to tell which dollars came from the tax estimate and which dollars came from caution.

A credit does not become spendable cash by optimism

If an estimate shows a credit, do not assume that amount arrives in the bank immediately. Carryforward, refund, offset, processing, and base-jurisdiction treatment need current confirmation. The number may be useful for planning without being available cash.

Keep the raw evidence

Preserve original ELD or distance reports, fuel-card files, receipts, statements, corrections, and the filed return according to the controlling recordkeeping requirements. Work from copies when you reconcile so the original trail does not get cleaned into something nobody can reconstruct later.

This is not paperwork for paperwork’s sake. The value of a clean quarter is that every mile and gallon can explain where it came from when the number is questioned later.

Do not “balance” the quarter by editing the side that is inconvenient

If jurisdiction miles are short by 280, do not simply add 280 to the state that makes the total work. If supported gallons are short by 50, do not assign them to the jurisdiction with the nicest tax result. A balancing entry without evidence fixes arithmetic and damages the record.

Trace the gap to the source: trip report, GPS/ELD history, odometer record, receipt, card statement, void, reversal, or fuel-type split. When the source explains the difference, make the correction and keep the reason. When the source does not exist, preserve the limitation and follow the base jurisdiction’s process.

A quarter that remains Not Ready is frustrating. A quarter made “ready” by invention is worse.

Keep a short reconciliation note with every correction: what changed, which source proved it, and who made the change. Six months later, that note is cheaper than reconstructing the quarter from memory.

A fuel-card pitch says 35 cents off. The quick math says 2,000 gallons a month should mean $700 in savings.

Then the truck runs the actual lanes.

Some gallons land outside the useful discount network. Monthly fees show up. A few “cheap” stops require extra route cost. By the time the statement closes, the famous 35 cents has been through customs.

The headline gets the billboard. The denominator gets the invoice.

First ask: 35 cents off what?

A discount is incomplete without its reference price. Retail-minus, cash-minus, cost-plus, rebate, and account-specific net pricing are not interchangeable. If the provider says “average” or “up to,” read the footnote and the population behind the claim before treating it as your expected result.

For example, AtoB’s public discount disclosure states an average truck-diesel discount and identifies the historical transaction population behind that marketing claim. Mudflap publishes a different network and fee structure. WEX publishes still another set of card, control, reporting, and network offerings. Those pages prove that provider structures vary. They do not prove what your account will save.

Make the discount pass through your real gallons

This worked example is not a provider claim. It uses stated assumptions.

• monthly gallons: 2,000;
• written price advantage where eligible: $0.35/gal;
• gallons that can realistically use that price on the operator’s lanes: 1,200;
• monthly program/account fees: $85;
• added monthly route cost attributable to using the discounted stops: $160.

The advertisement encourages this first multiplication:

2,000 gallons × $0.35 = $700

But only 1,200 gallons fit the usable discount network:

1,200 × $0.35 = $420 gross monthly benefit

Now bring the known costs back into the room:

$420 − $85 fees − $160 route cost = $175 net monthly benefit

Spread the surviving benefit over all 2,000 monthly gallons:

$175 ÷ 2,000 = $0.0875 per gallon

That is not an argument against fuel cards. It is an argument for using the correct denominator.

Fees need names, not a mystery bucket

Look for setup charges, monthly/account fees, per-card fees, per-transaction fees, out-of-network fees, funding or payment fees, subscription charges, late fees, returned-payment fees, and minimum-volume terms where they apply.

Separate routine expected costs from event charges. A late fee that never occurs should not be deducted every month as if it were inevitable. But an avoidable fee should not vanish from the written-term review either. It tells you what a process mistake costs.

Timing can make a saving awkward

A prefunded account may require cash before the fuel transaction. A charge product may draft after a short billing window. A credit product may have another schedule. If the program saves $175 a month but regularly creates a cash gap before freight pays, the savings and the timing problem can both be true.

Show both. Do not let annualized savings bulldoze the week’s bank balance.

Do not annualize a promotion by enthusiasm

If a discount is promotional, seasonal, lane-specific, or based on a temporary volume pattern, do not multiply one good month by twelve and call it a forecast. Annualize only when the month is reasonably representative and the written terms support continuing treatment.

And if the current setup already produces the better route-adjusted result, keep it. A comparison that is physically incapable of saying “keep your card” is not decision support. It is a sales funnel with arithmetic.

Use one month as a microscope, not a lifetime sentence

A representative month is useful because it gives the comparison real gallons, real lanes, and real transaction behavior. It is not permission to assume the next twelve months will be identical.

If the operation has strong seasonality or rotating customers, test more than one representative pattern. A card that wins during a Texas-heavy month may lose when the truck spends winter on a different network. Show the scenarios separately rather than blending them into an average nobody actually drives.

And keep promotions in their own lane. If a sign-up discount lasts 60 days, show the promotional period and the post-promotion economics. A temporary bargain can be worth taking without being allowed to masquerade as a permanent operating result.

Finally, compare the candidate with the setup you actually use today. A card does not create savings by existing; it creates savings only to the extent that the complete candidate result beats the complete current result on the same operating basis.

That comparison is the business case, not the cents-off headline.

A provider can advertise a huge network and still be a poor fit for a truck that runs the same awkward triangle every week.

Acceptance is not the same as a useful discount. A dot on a map is not the same as a stop you can reach without wasting the advantage. And a stop you can reach is not helpful if the account price there is weak.

A network map cannot fuel the truck. Your route does.

Count usable gallons, not map dots

Take a representative recent period and mark the lanes or repeated fuel areas. Then check each candidate card’s current account-specific pricing and eligible locations against those routes.

A “usable” stop should clear the practical test: truck access, fuel type, payment eligibility, workable hours, route fit, and a price advantage that survives any meaningful detour. Parking and service preferences can matter too, but do not turn personal preference into an economic claim unless it changes the decision.

The smaller headline wins by $22 a month

This example compares two fictional offers on the same 2,000-gallon month. It does not describe any real provider.

Card A

• advertised/entered advantage at eligible stops: 20 cents per gallon;
• usable gallons on actual lanes: 1,200;
• entered monthly fees: $10.

Card B

• entered advantage at eligible stops: 16 cents per gallon;
• usable gallons on actual lanes: 1,700;
• entered monthly fees: $20.

Card A:

1,200 × $0.20 = $240 gross benefit
$240 − $10 fees = $230 monthly net benefit

Card B:

1,700 × $0.16 = $272 gross benefit
$272 − $20 fees = $252 monthly net benefit

That is the distinction a national network count cannot answer. The relevant denominator is not “locations in America.” It is “gallons I can practically buy on the work I actually run.”

Run the bad-Tuesday test

The planned stop is down. Dispatch changes the lane. The card declines. The app loses the price. Now what?

Check the fallback: Can the card still buy fuel? Does the discount disappear? Is there an out-of-network fee? Does another payment method need to remain funded? How much of the month is likely to fall outside the good part of the network?

If 15% of the operator’s gallons normally become fallback purchases, those gallons belong in the comparison. Do not apply the best network price to 100% of volume because the map has good posture.

Cash timing rides with the card

A network can fit geographically and fail financially if the funding schedule fights the business. Confirm prefunding, billing window, draft timing, credit limit, payment method, returned-payment consequences, and any hold or reserve terms that apply.

Provider disclosures vary by product and account. Public pages may show network, pricing, fees, controls, or support, while the operator’s written offer can add billing and payment terms. That is why the written terms need to sit beside the map.

One truck does not need fleet theater

Spend controls, card lock/unlock, driver IDs, receipt capture, fraud alerts, reporting, and exports can be valuable. But give each feature a job. A solo owner-operator may care more about price visibility and a reliable fallback than a complicated hierarchy of driver permissions.

A small fleet may need those controls much more. Same feature. Different operational value.

Support should be tested before the pump declines

Verify the support channel, hours, decline process, lost-card control, dispute process, and replacement path while nothing is wrong. “24/7 support” is only useful when you know what that channel actually handles.

Then make the decision from the whole setup. If a card requires the operation to reroute around the advertisement, the network is not serving the business. The business is serving the network.

Coverage percentage needs a route story behind it

“85% of gallons are usable” is only useful if the 85% came from actual or deliberately planned lanes. Do not generate the percentage by counting pins inside a 50-mile circle and calling every one practical.

For recurring lanes, mark the normal fuel windows, not every station the truck could theoretically reach. A location that requires an inconvenient backtrack, unreliable parking, or a payment method the account cannot use may still be “in network” while being operationally useless.

That is why HSHQ treats usable share as an operator input that needs evidence. The map supplies candidates. The operation decides which dots are real choices.

If the route pattern changes materially, rerun the fit check. Network value belongs to the work being hauled now, not to the lanes the truck ran when the card was first opened.

Offer A says 20 cents off. Offer B says 28 cents off. The obvious winner is B, assuming we are comparing two billboards.

For an operating decision, the offers need the same gallons, same lanes, same time period, same fee treatment, and a price method that can actually be translated into dollars.

Two offer sheets can both be beautiful and still refuse to be compared.

Freeze the operating facts before the sales numbers start moving them

Choose one representative month or a clearly labeled planning month. Keep total gallons and transaction count fixed across the options. Then apply each offer only to the gallons that can realistically use it.

If one option is retail-minus and another is cost-plus, do not force a winner until the cost-plus base and markup are known for the comparison. If a rebate is delayed, keep cash timing visible. If one fee is Unknown, the final dollar ranking is Unknown.

The smaller discount wins by $15

This example uses fictional offers and stated inputs:

• monthly gallons: 2,000;
• transactions: 20;
• same representative lanes and month for both options.

Offer A

• 20-cent advantage on 80% of gallons;
• $20 monthly fee;
• $0.50 transaction fee.

Offer B

• 28-cent advantage on 50% of gallons;
• $5 monthly fee;
• no entered transaction fee.

Offer A usable gallons:

2,000 × 80% = 1,600 gallons

1,600 × $0.20 = $320 gross benefit

20 transactions × $0.50 = $10 transaction fees

$320 − $20 monthly fee − $10 transaction fees
= $290 monthly net benefit

Offer B:

2,000 × 50% = 1,000 usable gallons

1,000 × $0.28 = $280 gross benefit

$280 − $5 monthly fee
= $275 monthly net benefit

The reason is not mysterious: more gallons can actually use Offer A.

Now try to break the result

What if Offer B’s network fit improves next month? What if Offer A’s fee is promotional? What if one card’s price method changes by merchant? What if the “usable gallon share” came from a guess rather than a recent lane history?

A good comparison keeps those assumptions visible so the operator can see what would reverse the result. If moving one uncertain input flips the winner, the correct outcome may be Compare Further rather than “switch.”

Read the agreement after the calculator clears its throat

Price is not the only written term. Confirm funding or credit structure, draft timing, account and transaction fees, late and returned-payment charges, purchase controls, liability for unauthorized use, dispute procedure, data/export access, suspension rules, term, renewal, termination, and what happens to balances or rewards at exit.

A friendly sales summary can point you toward those terms. It does not replace them. “That should be fine” is conversationally pleasant and contractually unemployed.

If a required term is Unknown, stop ranking

Suppose Offer B uses cost-plus pricing but the quote does not identify the cost basis or markup needed for your lane comparison. Do not substitute a retail-minus estimate and keep the Offer B logo at the top of the spreadsheet.

The correct result is:

Do not cut up the old card because the new spreadsheet is exciting

Before switching, confirm approval, activation or funding, account-specific price visibility, practical route coverage, final written terms, and a workable fallback. A preliminary comparison earns the next check. It does not earn the right to strand the truck at a pump with a beautifully formatted decision report.

And if the current setup still leaves more money after the same-basis comparison, keep it. HSHQ is not offended.

Keep the losing offer’s good features visible

A dollar winner does not erase every advantage of the other offer. One card may lose by $15 a month but provide a better funding schedule, stronger controls, easier exports, or a network fallback the operation values.

Show those differences beside the $15 result. Then decide whether the non-price feature is worth at least $15 a month to this operation. That is a much cleaner question than declaring one card “better.”

If the feature cannot be priced honestly, leave it qualitative and specific: “Offer B provides the required driver-level controls; Offer A does not.” Do not invent a fake dollar value just to make every row add up. Some business decisions contain a number and a boundary at the same time.

Save the source date for each written offer. Fuel-card pricing and fees can change, and a comparison built from two different months can look precise while comparing terms that never existed at the same time.