IFTA Fuel Tax Calculator

Under the International Fuel Tax Agreement, a carrier files one quarterly return that splits fuel tax among every U.S. state and Canadian province its qualified trucks drove in. Tax is owed on the fuel used in each jurisdiction, with credit for tax already paid at the pump there. This calculator does the arithmetic from your mileage and fuel records and shows the balance for each line.

How to use this tool

1. List each jurisdiction on its own line with taxable miles, tax-paid gallons bought there and the tax rate.
2. Copy the rates for the quarter from the IFTA tax rate matrix.
3. If you have non-IFTA miles or bulk fuel, enter the true total miles and gallons.
4. Read the fleet MPG, the net tax for each jurisdiction and the total due or credit.

Formula

Fleet MPG = total miles ÷ total gallons

Taxable gallons = jurisdiction miles ÷ fleet MPG

Tax due = (taxable gallons − tax-paid gallons) × rate

A positive amount means you used more fuel in that jurisdiction than you bought there; a negative amount is a credit. Credits from one jurisdiction offset amounts owed to others on the same return.

Example

A truck ran 3,280 miles on 430 gallons: 7.63 MPG. In Illinois it drove 980 miles, using 128.44 gallons but buying none, so at a sample $0.66 rate it owes $84.77. In Iowa it drove 410 miles (53.74 gallons) but bought 230 gallons, a credit of $57.29 at $0.325. With Ohio and Indiana the quarter nets to $61.65 due.