IFTA Tax Estimator
Log the miles you ran and the gallons you bought in each state, and this estimator settles your quarter the way the IFTA return does — who you owe, who owes you, and the net either way. Rates are the official 2026 Q2 diesel rates from the IFTA Inc. matrix, refreshed every quarter.
| State | Miles driven | Gallons bought | Tax rate ($/gal) | Remove |
|---|
How IFTA actually settles
gallons burned in a state = miles in that state ÷ fleet MPG
net = burned × state rate − gallons purchased there × rate
You pay where you burn; you get credit where you buy.
FAQ
How does IFTA actually settle up?
IFTA allocates fuel tax by where you burn, not where you buy. Say you run 1,200 miles in Texas with a 6 MPG fleet average — that's 200 gallons burned in Texas, and Texas taxes all 200 of them no matter where you bought the fuel. Every gallon you did buy at Texas pumps already paid Texas tax, so it comes back as a credit. Your quarterly return nets those two numbers out in every jurisdiction you touched.
Which states charge an IFTA surcharge?
Indiana, Kentucky and Virginia. The surcharge is collected on your quarterly return, not at the pump, and it's levied on gallons burned in the state — so you can't route around it by fueling elsewhere. This tool's simple model shows base rates only; budget the surcharge on top if you run those states.
When are IFTA quarterly returns due?
The last day of the month after each quarter ends: April 30 (Q1), July 31 (Q2), October 31 (Q3) and January 31 (Q4). If that lands on a weekend or holiday, the due date rolls to the next business day.
What fleet MPG should I use?
Your audited IFTA MPG: total fleet miles ÷ total gallons purchased for the quarter, straight from your own mileage and fuel records. Not the brochure number — the gap between a spec-sheet 7.5 and a real-world 6.2 changes every line of the return.
Related tools
Trip fuel cost · Cost per mile · Weekly fuel surcharge chart
Rate pages: California and more coming.
Data updated: 2026Q2 · Source: IFTA Inc. official tax matrix