Calculators / IFTA Estimate

IFTA Estimate Calculator

A quarterly IFTA bill comes from one thing: driving miles in high-tax states while buying fuel in low-tax ones. This is a directional sanity check on that gap before quarter-end, not a filing tool. It does not replace your return or your records. Runs in your browser. Numbers stay on your machine.

Your rig Sets the MPG basis. Edit any field after.

Flatbed / step-deck (Class 8) Hotshot (1-ton dually)

Are you even subject to IFTA? IFTA covers a vehicle with three or more axles, or one used in a combination whose combined gross or registered weight is over 26,000 lbs. A Class 8 always qualifies. A 1-ton pickup plus a gooseneck only qualifies if the combined registered weight tops 26,000 — many hotshots register at or under 26,000 specifically to stay out of IFTA, IRP, and the logbook threshold at once.

3+ axles, or combined weight over 26,000 lbs 2 axles and 26,000 lbs or under

Total miles this quarter, every jurisdiction All miles on the IFTA plates: loaded, empty, deadhead, bobtail, personal. Counting only dispatched miles is the most common way operators under-report and get a surprise at audit. Exclude only miles run under a trip permit.

Fleet MPG for the quarter Total miles divided by total gallons purchased, not a guess off the spec sheet. This is what the return uses. Class 8 flatbed runs 5.5–7. A 1-ton hotshot runs 9–13. A wrong MPG here is the single biggest error in a self-serve estimate.

Share of your miles in higher-tax states Roughly what percent of the quarter’s miles ran in higher-tax jurisdictions — California, Pennsylvania, Washington, Oregon, Illinois, and the Northeast corridor. The rest is treated as lower-tax (Texas, Oklahoma, Missouri, and most of the South and Gulf). Ballpark is fine; this is a sanity check.

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Share of your fuel bought in those higher-tax states What percent of your gallons you actually pumped in the higher-tax states. If you chase cheap fuel in the South and run loads up the Northeast, this number is far below the miles number above — that gap is your bill.

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Share of your miles in Indiana, Kentucky, or Virginia These three run a surcharge on top of the base tax. It is charged on the fuel you burn there and there is no pump credit for it, so buying more fuel in those states never reduces it. Leave at 0 if you stay out of the I-65, I-64, and I-81 corridors.

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What actually drives the bill

IFTA settles fuel tax to where you burned the fuel, not where you bought it. You get credit for tax paid at the pump and you owe tax on miles run, jurisdiction by jurisdiction. Net it out and the number is driven by one spread: the average tax rate of the states you drove versus the average rate of the states you fueled in. Drive the Northeast, fuel in the Southeast, and you will owe. That is the case this tool wants you to see before quarter-end, while you can still change where you buy the next two months of fuel.

The surcharge nobody nets correctly

Indiana, Kentucky, and Virginia add a surcharge on top of the base tax. It is assessed on the fuel you consume in the state, and unlike the base tax there is no offsetting credit at the pump — you cannot buy your way out of it. New authorities running the I-65, I-64, or I-81 corridors routinely model it as a normal credit-eligible tax and come up short on the return. This calculator always adds it and never credits it.

Are you even subject to IFTA

Before any of the math matters: IFTA covers vehicles with three or more axles, or combinations over 26,000 lbs gross or registered weight. A Class 8 always qualifies. A 1-ton pickup plus a trailer only qualifies if the combined registered weight tops 26,000 lbs, which is why many hotshots register at or below that line on purpose. If you are not IFTA-qualified, occasional trips are handled with trip permits, not a quarterly return.

What this version leaves out on purpose

This is a directional check, not your return. It uses two representative blended rates, not the live per-jurisdiction matrix, and it ignores Canada, off-road and PTO mileage deductions, bulk fuel, and trip-permit miles. States like Pennsylvania and California run well above the “higher-tax” blend used here, so treat a heavy-Pennsylvania quarter as a floor. File from your actual mileage and fuel records, and keep four years of distance logs and fuel receipts — that retention requirement is the part the estimate cannot do for you. See IFTA, IRP & Tax Recordkeeping for the records side, and browse the Shop for the full Rate Per Mile Calculator.