IFTA Fuel Tax Calculator

Enter the miles you ran and the gallons you bought in each state this quarter, and this IFTA calculator estimates your fuel tax for the return: your fleet mpg, the tax or credit for each state and the net amount due. It uses the diesel rates from the IFTA, Inc. tax rate matrix for the 4th quarter 2026.

IFTA balances what you paid at the pump against what you owe each state for the miles you drove there. Buy cheap fuel in one state and run miles in another, and the return sorts out the difference.

How to use the IFTA calculator

1. Get your miles by state. Your ELD's IFTA or state mileage report for the quarter is the easiest source. Include loaded and empty miles, and every state you drove in, even for a few miles.
2. Get your gallons by state. Add up fuel receipts or your fuel card's state report. Only count tax-paid fuel bought at the pump and put in the truck.
3. Enter each state. Pick the state, then its miles and gallons. A state where you drove but didn't buy fuel gets zero gallons.
4. Read the net. A positive number is tax you'll pay with the return. A minus is a credit.

How IFTA tax is figured

The rates come from the IFTA, Inc. tax rate matrix, which every member state and province reports to each quarter. Your base state's own return and instructions are the final word on how to file. IFTA, Inc. explains the agreement itself on its home page.

Diesel rates used, 4th quarter 2026

U.S. dollars per gallon for special fuel (diesel), lower 48 only. Two notes for this quarter: Ohio reported a rate reduction holiday from October 4, 2026 to January 2, 2027, so Ohio miles and gallons before and after October 4 go on separate lines. Oregon has no IFTA diesel rate for qualified vehicles, because it charges a weight-mile tax instead.

Worked example

The calculator's example is a made-up quarter: 8,000 miles through Texas, Oklahoma, Arkansas, Tennessee and Kentucky, with 1,230 gallons bought in three of those states. That's a fleet average of about 6.5 mpg.

• Texas: 4,200 miles needs about 646 gallons. 600 were bought there, so a small amount is owed.
• Oklahoma: fuel was bought there beyond what the miles used, so it's a credit. Oklahoma's rate is one of the lowest, which is why carriers often fuel there.
• Arkansas: miles but no fuel, so the full tax on about 138 gallons is owed.
• Tennessee: another credit for extra fuel bought.
• Kentucky: no fuel bought, so the regular rate and the surcharge are owed on the gallons used.

Credits in one state offset tax in another. That's why a quarter with fuel bought in low-tax states can end with a small net bill, or a credit, even after thousands of miles.

How to read your result

Deadlines and who files

You need an IFTA license if your truck has two axles and a gross or registered weight over 26,000 lbs, has three or more axles, or runs in a combination over 26,000 lbs, and it crosses state lines. Most box trucks under 26,001 lbs don't need one.

You file with your base state every quarter, even in a quarter you didn't run. Returns are due the last day of the month after each quarter: January 31, April 30, July 31 and October 31. The return for the 4th quarter of 2026 is due January 31, 2027.

Keep your trip records and receipts. IFTA audits check them, and when records are missing, the state can estimate the tax for you, rarely in your favor.

Common mistakes

• Leaving out empty miles. IFTA counts every mile on public roads, loaded or not.
• Counting fuel for reefer units. Reefer fuel from a separate tank isn't truck fuel. Only count what went into the truck.
• Missing small states. Ten miles through a state still goes on the return.
• Using last quarter's rates. Rates change every quarter in some states. This tool is updated each quarter.
• Losing receipts. A fuel card that reports by state saves hours at quarter end, and your ELD records the miles. Our hours of service guide covers what the ELD must record.
• Skipping a zero quarter. You still file, even with no miles.

Keeping it simple

Most IFTA headaches come from missing records, not math. Clean ELD state mileage, a fuel card and one folder per quarter make the return a 20-minute job. Our compliance calendar lists every IFTA deadline with the rest of your yearly filings, and the Form 2290 calculator and MCS-150 due date tool handle two more.

Fuel tax also changes what a load is worth. Fuel bought in a high-tax state costs more at the pump, but you get credit for that tax on your return, so the real cost is the state where you drive the miles.

For the per-mile side of fuel, see the fuel surcharge calculator and the cost per mile calculator. Dispatch doesn't include tax filing, but your dispatcher can route fuel stops when you ask. See how we work with owner-operators, or check the glossary entry on IFTA.

Estimates only, for diesel. Your base state's return decides the real amount. This isn't tax advice.