Get a feel for your fuel tax.
Put in the miles you ran and the gallons you bought in each state. We work out your fleet MPG, the gallons each state says you burned there, and what you owe or get back.
| Jurisdiction | Miles run | Gallons bought | Tax |
|---|---|---|---|
| −$62.80 | |||
| $15.96 | |||
| $169.74 |
An estimate, not a return.
Your fleet MPG is total miles divided by total gallons. For each state, the gallons you're taxed on are that state's miles divided by your MPG. Subtract the gallons you actually bought there, multiply by that state's rate, and that's the line. Surcharge states (Indiana, Kentucky, Virginia) carry a second line we'd add for you in the real return.
This calculation is for planning only. It does not include exemptions, interest, penalties, or currency conversion. Confirm your final figures and rules with your base jurisdiction.
Rather not type any of this? Upload your ELD export and fuel statement instead — the same numbers, filled in for you, with the paperwork behind every one. First return is free. Need a rate? Look it up.
Get a filing-ready returnHow to calculate IFTA fuel tax: a worked example
IFTA fuel tax is worked out per state: the fuel each state says you used there, less the tax-paid fuel you bought there, times that state's rate. Here is one truck's Q3 2026 (July to September), using that quarter's diesel rates from IFTA, Inc.'s rate table. It drove 10,000 miles and bought 1,600 gallons, all tax-paid at the pump.
- Work out your fleet miles per gallon. Divide all the miles you drove by all the gallons you bought: 10,000 ÷ 1,600 = 6.25 miles per gallon, rounded to 2 decimals.
- Work out the fuel each state says you used there. Divide the miles you drove in that state by your miles per gallon, and round to a whole gallon. These are your taxable gallons.
- Take off the tax-paid fuel you bought in that state. You already paid that state's tax at the pump, so you get credit for it. Keep the receipts.
- Multiply what is left by the state's rate. A negative number is a credit: you bought more there than you used there.
- Add up every state. The total is what you pay, or get back, for the quarter.
| State | Miles | Taxable gallons | Tax-paid gallons bought | Net gallons | Rate (US$/gal) | Tax or credit |
|---|---|---|---|---|---|---|
| Texas | 6,000 | 960 | 1,200 | -240 | $0.2000 | $48.00 credit |
| Oklahoma | 2,500 | 400 | 400 | 0 | $0.1900 | $0.00 |
| Arkansas | 1,500 | 240 | 0 | 240 | $0.2850 | $68.40 |
| Total | 10,000 | $20.40 | ||||
In this example the truck owes $20.40 for the quarter. Some states also charge a surcharge on every taxable gallon, with no credit for fuel bought there; the calculator above includes it.
Steps as set out in the Instructions for Form IFTA-101, New York State Department of Taxation and Finance, read 2026-10-22. Your base jurisdiction's return may lay them out differently; check its instructions before you file.