Free tool
IFTA fuel tax calculator
Add a row per state, enter your miles and the gallons you bought there, and see your net IFTA tax in real time. No login.
Miles & fuel by jurisdiction
Q2 2026Rates: diesel, Q2 2026 (April 1 – June 30, 2026). Rates change every quarter. Verify the current matrix at iftach.org before you file. Runs entirely in your browser.
| Juris | Taxable gal | Net tax |
|---|---|---|
| CA | 194.3 | $110.97 |
| TX | 145.7 | $-22.86 |
* Oregon uses a weight-mile tax, not IFTA fuel tax.
How it works
From trip sheet to quarterly filing
IFTA exists so a truck that fuels in one state but drives through five others pays each state its fair share of fuel tax. You report the miles you drove and the gallons you bought in every jurisdiction, and the settlement nets out who you owe and who owes you.
The hard part is the bookkeeping, not the math. Rigbird lets you log fuel purchases and trip miles as you go, then builds the quarterly worksheet for you. Start with the free calculator above, then look up your state's diesel rate or sign up to save your quarters.
Your fleet MPG is total miles divided by total gallons. For each state, taxable gallons equal the miles you drove there divided by your fleet MPG. Subtract the gallons you actually bought (and paid tax on) there to get net taxable gallons, then multiply by that state's diesel rate. Add it all up across states to get what you owe or get refunded.
File IFTA from real trip data
Log fuel and miles in Rigbird and the quarterly worksheet builds itself.