Filing IFTA taxes every quarter is one of the most confusing administrative tasks owner-operators face. The math isn’t hard — but getting it wrong means penalties. This free IFTA calculator walks you through every state you drove, calculates your gallons consumed vs. purchased, applies the correct Q2 2026 diesel or gasoline rate for each jurisdiction, and tells you exactly what you owe — or what credit you have coming.
No signup. No account. Updated every quarter.
| State | Miles driven | Gallons purchased | Tax rate |
|---|
Indiana, Kentucky, Virginia, New York, and New Mexico impose surcharges on top of base IFTA rates. Surcharges are always owed and do not generate credits.
How to Use This IFTA Calculator
Enter your carrier name, select your quarter, base state, and fuel type. Set your average MPG — most diesel trucks run between 6 and 7. Then add each state you drove through this quarter and enter the miles driven and gallons purchased in that state. If you fueled up in Texas but drove through Oklahoma without stopping, enter 0 gallons for Oklahoma. Hit Calculate and the tool handles the rest — gallons consumed vs. purchased, tax rate per state, surcharges for Indiana, Kentucky, Virginia, New York, and New Mexico, and your final net tax due or credit.
What Is IFTA and Who Needs to File?
IFTA — the International Fuel Tax Agreement — requires owner-operators and carriers running qualified motor vehicles across member jurisdictions to file a quarterly fuel tax return with their base state. A qualified motor vehicle is any truck used in two or more member jurisdictions with two axles and a gross vehicle weight over 26,000 lbs, or any vehicle with three or more axles regardless of weight. If that describes your operation, you file four times a year: April 30, July 31, October 31, and January 31.
How IFTA Tax Is Calculated
IFTA works on a simple principle: you pay tax based on where you consumed fuel, not where you bought it. The calculator figures out how many gallons you consumed in each state based on your miles and MPG, then compares that to what you actually purchased there. If you consumed more than you bought in a high-tax state like Pennsylvania or California, you owe tax to that state. If you bought more than you consumed — say you fueled up heavily in a low-tax state like Texas — you get a credit. The net of all those state calculations is your final tax due or credit for the quarter.
IFTA Filing Deadlines 2026
| Quarter | Period | Filing Deadline |
|---|---|---|
| Q1 2026 | January – March | April 30, 2026 |
| Q2 2026 | April – June | July 31, 2026 |
| Q3 2026 | July – September | October 31, 2026 |
| Q4 2026 | October – December | January 31, 2027 |
Late filing carries a penalty of $50 or 10% of the net tax due — whichever is greater. Zero-mile quarters still require a filing.
States With IFTA Surcharges
Five states charge a surcharge on top of the base fuel tax rate. Unlike standard IFTA tax, surcharges are always owed — they do not generate a credit even if you over-purchased fuel in that state.
Indiana — $0.6100/gal surcharge Kentucky — $0.1050/gal surcharge Virginia — $0.1430/gal surcharge New York — $0.0095/gal surcharge New Mexico — $0.0100/gal surcharge
If any of these states are on your route this quarter, the calculator includes the surcharge automatically in your total.
A Note on Oregon
Oregon does not participate in the standard IFTA fuel tax system. Instead, Oregon uses a weight-mile tax assessed separately through the Oregon Department of Transportation. If you drive through Oregon, enter your miles as normal — they count toward your total mileage — but no per-gallon IFTA tax is calculated for Oregon. You will need to handle Oregon’s weight-mile tax separately through ODOT.
Disclaimer
This calculator uses Q2 2026 diesel and gasoline tax rates sourced from the IFTA Inc. tax rate matrix and is for estimation purposes only. Tax rates change every quarter — always verify current rates at iftach.org before filing your official return. This tool does not constitute tax advice. Consult your base state’s IFTA instructions or a qualified tax professional before filing.