IFTA Fuel Tax Calculator

IFTA is the International Fuel Tax Agreement, a system used across the lower 48 US states and 10 Canadian provinces to simplify fuel tax reporting for vehicles that cross state or provincial lines. If you operate a qualified motor vehicle — generally one over 26,000 pounds or with three or more axles — across two or more member jurisdictions, you file a single quarterly IFTA return through your base jurisdiction.

First you add up your total miles and total gallons across every jurisdiction to get your fleet MPG. For each jurisdiction, taxable gallons equal the miles driven there divided by that fleet MPG. Tax due is taxable gallons times the jurisdiction's tax rate, and tax paid at the pump is the gallons you bought there times that same rate. The difference is what you owe or are credited for that jurisdiction.

If you buy more fuel in a state than your mileage there consumed, you have effectively prepaid more tax than you owe that jurisdiction, so it shows as a credit. Buying fuel in low-tax states and burning those miles in higher-tax states is a common reason a return nets out to a credit in some jurisdictions and a balance owed in others.

Your base jurisdiction publishes an official IFTA tax rate matrix every quarter, and the full matrix is posted on the IFTA, Inc. website. Always pull the current quarter's rates — they change frequently — and watch for jurisdictions that add a separate surcharge on top of the base rate.

You can fold a surcharge into the tax rate you enter for that jurisdiction, but some states require the surcharge to be reported on a separate line of the official return. This tool gives you a fast estimate of your overall position; for the exact filing, follow your base jurisdiction's surcharge instructions.

Use total miles traveled in each jurisdiction, including loaded, empty, and personal miles driven by the qualified vehicle. Use gallons purchased in each jurisdiction, supported by fuel receipts. Keeping accurate trip records and fuel receipts is what makes your IFTA return defensible if you are audited.

No. This is a planning estimate only, not an official filing. It helps you forecast what you will owe and catch errors before deadline, but you must still file your actual quarterly return through your IFTA account using your base jurisdiction's official forms and rates.

Yes, the calculator is completely free with no signup required. Your jurisdiction rows are saved locally in your browser so they persist between visits — nothing is uploaded to a server. Clearing your browser data will erase your saved values.