01 / Your quarter
The rows hold an example. Replace them with your own: miles from your ELD report by state, gallons from your fuel-card statement or receipts. Everything stays in your browser.
02 / The method
1. Fleet MPG. All miles for the quarter divided by all gallons bought, rounded to two decimals. One number for the whole quarter, not per state.
2. Taxable gallons in each state = miles driven there ÷ fleet MPG. This is the fuel the state considers burned on its roads.
3. Net tax = (taxable gallons − gallons bought in that state) × that state’s rate. Buy more than you burn there and you get a credit; drive through without fuelling and you owe. Kentucky and Virginia add a surcharge on taxable gallons that fuel purchases do not offset.
4. One return, one payment. You file with your base state, which settles with the others. Returns are due April 30, July 31, October 31 and January 31 — and a return is required even for a quarter with no miles.
Practical point: where you fuel changes the result. Filling up in a low-tax state and driving through a high-tax one leaves a balance due; the pump price already told you that, IFTA just settles it.
Rates: IFTA, Inc. tax rate matrix, Special Diesel, U.S. dollars per gallon, refreshed automatically. Oregon has no IFTA fuel tax on diesel — heavy trucks pay its weight-mile tax instead.
This is an estimate for planning, not a filed return. It assumes all miles are taxable and diesel only, and it leaves out interest, penalties, toll-road exemptions and rate changes inside a quarter. Your base state’s return is what counts.
Start with a conversation
Book a free 15-minute review — bring your questions, leave with a plan.