Taxes and compliance
IFTA Fuel Tax Calculator
What you owe or get back for the quarter, state by state, using the official IFTA diesel rates.
- Free, no sign-up
- Shows the math
- Official sources
- PDF export with Pro
Your result
How this calculator works
Fleet MPG = total miles ÷ total gallons. Then for each state or province: taxable gallons = miles there ÷ fleet MPG, and net tax = taxable gallons × rate − tax-paid gallons × rate. Add up the lines. A positive total is what you pay your base jurisdiction. A negative total is a credit or refund.
IFTA treats all your fuel as if you burned it evenly across every mile. So you owe each jurisdiction tax on its share of the fuel, and you get credit for the tax you already paid at the pump there. Buy cheap fuel in one state and drive miles in another, and the return moves the tax to where the miles were.
This follows the standard IFTA return: MPG is rounded to two decimals and gallons to whole gallons (IFTA Procedures Manual P720). Kentucky and Virginia also charge a surcharge on every taxable gallon used there. You get no credit against the surcharge for fuel you bought in those states, because the surcharge isn't collected at the pump (Kentucky KRS 138.695, Virginia § 58.1-2706).
Rates come from the IFTA, Inc. tax rate matrix for the quarter you pick. Oregon shows no rate because trucks there pay Oregon's weight-mile tax instead, but Oregon miles still count toward your MPG. See every rate on the IFTA fuel tax rates by state page.