IFTA Calculator – Calculate Your Fuel Tax Quickly & Easily

Use this IFTA calculator tool to accurately determine your fuel tax based on miles driven and fuel purchased across different states.

IFTA Calculator

How to use the IFTA Calculator

Enter the total miles travelled, the amount of fuel you have purchased in gallons, and the average miles per gallon (MPG) your vehicle gets. Press the Calculate button to see the result.

How it works

This IFTA calculator computes the amount of fuel you should have used based on the miles travelled and the average MPG your vehicle gets. The result is the difference between the fuel you should have used and the fuel you have purchased; this figure could be used for estimating your IFTA tax liability.

Result = (Miles Travelled / Average MPG) – Fuel Purchased


The calculator assumes consistent fuel efficiency across all travel and doesn’t take into account changes in terrain, load, or driving style. Additionally, this calculation may not reflect actual IFTA tax rates as those vary by jurisdiction and must include fuel tax rates applied per state. The result is purely for an estimation and does not replace professional IFTA reporting.

Other Resources and Tools