IFTA fuel tax calculator
The full fuel-tax math per jurisdiction: what you burned, what you already paid at the pump, and the net you owe (or the credit you're carrying).
- Q2 2026 diesel rates
- Pump-credit math built in
- Negative balances handled
Reading your result
Positive due = you burned more fuel in that state than you bought there — you owe the difference at that state's rate. Negative = you overbought there; the credit nets against other states on the same return. The bottom-line total (one number) is what you pay your base state, or the refund you can roll forward.
Surcharge states are different: Indiana, Kentucky and Virginia charge their surcharge on every gallon you burn in-state, with no credit for pump purchases — so buying extra fuel there never reduces the surcharge.
Frequently asked questions
Why is my California line always positive?
California's diesel rate is the nation's highest — over $0.97/gal. Fuel bought in Arizona or Nevada is cheaper at the pump but earns credit at those states' lower rates, so CA miles almost always produce net tax due.
The calculator shows a total credit. Do I still file?
Yes — IFTA returns are mandatory every quarter, even at $0 or with a refund due. Most states let you roll credits forward or request a refund.