IFTA calculator
Enter your miles and gallons purchased in each state to compute fleet MPG, taxable gallons, and the net IFTA tax you owe or are credited per jurisdiction — with a quarterly total. Nothing is saved; the math runs in your browser.
Fleet MPG
10.62
2,070 mi ÷ 195.0 gal
Net tax due
$13.97
across 3 jurisdictions
| Juris. | Taxable gal | Rate | Owed | Paid | Net |
|---|---|---|---|---|---|
| TX | 116.8 | $0.200 | $23.36 | $33.00 | -$9.64 |
| OK | 29.2 | $0.200 | $5.84 | $0.00 | $5.84 |
| CA | 49.0 | $0.936 | $45.85 | $28.08 | $17.77 |
Diesel rates as of Q1 2025 (Jan–Mar 2025). Reference data only. IFTA rates change every quarter and vary by fuel type; some jurisdictions (IN, KY, VA) also add a surcharge that is not modeled here, and Oregon uses a weight-mile tax instead of a fuel tax. Always verify against your base jurisdiction’s official IFTA rate sheet before filing. This tool does not store anything you enter.
What IFTA is and who has to file
The International Fuel Tax Agreement (IFTA) lets carriers who run qualified motor vehicles across state or provincial lines report all of their fuel tax on a single quarterly return, instead of filing in every jurisdiction. If you operate a truck over 26,000 lbs (or with three or more axles) across two or more IFTA jurisdictions, you file an IFTA return every quarter — even the quarters you didn’t run.
How the reconciliation works
You pay fuel tax at the pump wherever you buy diesel, but IFTA charges you tax based on where you actually drive. The return trues that up: states where you burned more fuel than you bought fuel collect the difference, and states where you bought more than you burned issue a credit. Your fleet MPG is the pivot — it converts the miles in each state into taxable gallons.
Filing deadlines
Returns are due one month after each quarter closes: April 30, July 31, October 31, and January 31. Missing a deadline means penalties and interest, and IFTA compliance problems can put a hold on your registration — which is why keeping clean mileage and fuel records all quarter, not scrambling at the deadline, is what separates carriers who file in minutes from those who lose a day to it.
The rates in this tool are a labeled reference snapshot; verify your base jurisdiction’s official rates before filing.
Frequently asked questions
- How is IFTA tax calculated?
- IFTA reconciles the fuel tax you paid at the pump against the tax you actually owe based on where you drove. First you find your fleet MPG (total miles ÷ total gallons purchased across all jurisdictions). Then, for each state, taxable gallons = miles driven there ÷ fleet MPG. Multiply taxable gallons by that state's tax rate to get tax owed, subtract the tax you already paid on fuel bought there, and the difference is what you owe or are credited in that jurisdiction. Sum every jurisdiction for your net quarterly tax.
- When are IFTA returns due?
- IFTA returns are filed quarterly. The deadlines are the last day of the month following the quarter: April 30 for Q1 (Jan–Mar), July 31 for Q2 (Apr–Jun), October 31 for Q3 (Jul–Sep), and January 31 for Q4 (Oct–Dec). If a due date falls on a weekend or holiday, it moves to the next business day. You must file even for a quarter with no miles.
- What is fleet MPG and why does it matter?
- Fleet MPG is your total miles divided by your total gallons purchased for the quarter. IFTA uses this single average to convert the miles you ran in each state into 'taxable gallons' for that state. A higher fleet MPG means fewer taxable gallons and less tax owed, so accurate odometer and fuel-receipt records directly affect your bill.
- Are these IFTA tax rates current?
- The rates bundled in this calculator are a labeled reference snapshot for the quarter shown, and they are diesel rates for the 48 contiguous US states plus DC. Official IFTA rates change every quarter and vary by fuel type, and some jurisdictions add surcharges not modeled here. Always confirm against your base jurisdiction's current IFTA rate sheet before you file.