IFTA Fuel Tax Estimator
Estimate your quarterly IFTA tax before you file. See what you owe or get credited per state.
Fleet Info
Total miles / total gallons for the quarter. Most semis: 5.5-7.5 MPG.
States
Add each state you drove through this quarter. Enter miles driven and gallons purchased in that state.
Quarter
Estimated IFTA Tax
Disclaimer: This is an estimate. Actual IFTA tax rates change quarterly. Always verify current rates at iftach.org before filing. This tool uses approximate 2026 Q1 rates.
Need help with IFTA or trucking compliance?
Read our IFTA & IRP Guide →How IFTA Tax Is Calculated
Calculate your fleet MPG
Total miles driven in the quarter divided by total gallons purchased = your fleet MPG. This single number drives everything.
Figure gallons consumed per state
Miles driven in each state divided by your fleet MPG = gallons consumed in that state. This is how much fuel each state says you "used" — even if you didn't buy any fuel there.
Compare consumed vs purchased
If you consumed more than you purchased in a state, you owe that state tax on the difference. If you purchased more than you consumed, the state owes you a credit.
Apply each state's tax rate
Each state has a different fuel tax rate per gallon. The net gallons (consumed minus purchased) times the tax rate = your tax owed or credit per state.
Why You Might Owe Even After Paying at the Pump
When you buy fuel, you pay that state's fuel tax at the pump. But IFTA redistributes tax based on where you drove, not where you bought fuel. If you buy all your diesel in a low-tax state but drive mostly through high-tax states, you'll owe the difference. The opposite is also true — you can get credits if you buy fuel in high-tax states but drive through low-tax ones.