IFTA Fuel Tax Calculator

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Rules, prices and device details on this page were checked October 2026 against the official sources listed at the bottom. Where a provider doesn't publish a number, we say so instead of guessing.

Want to know what your IFTA return will look like before you file? This calculator estimates the tax you owe, or the credit you get back, for each state and province based on the miles you drove and the fuel you bought there. It's an estimate, not a filed return, but it's a quick way to plan cash flow and spot mistakes. The rates come from the IFTA, Inc. tax rate matrix for the quarter shown on the calculator.

Use the Calculator

1. Pick the jurisdiction for each row.
2. Enter the miles you drove there this quarter.
3. Enter the tax paid gallons you bought there.
4. Add a row for every state or province you drove in, even if you didn't buy fuel there.
5. Check the results table for each jurisdiction and your total.

Enter Miles and Gallons by State

Your numbers need to cover all of your qualified vehicles for the quarter. Miles come from your trip records, GPS or ELD reports. Gallons come from your fuel receipts or fuel card statements. Only count tax paid gallons, meaning fuel where the state's tax was included in the pump price.

The calculator then works out your fleet's average miles per gallon: total miles divided by total gallons. That one number drives everything else, so double check both totals.

How Tax Rates Apply

For each jurisdiction, the math goes like this:

1. Taxable gallons = miles in that jurisdiction divided by your fleet MPG.
2. Net taxable gallons = taxable gallons minus tax paid gallons bought there.
3. Tax due = net taxable gallons times that jurisdiction's rate.

Here's a quick example using 4Q2026 diesel rates from the IFTA matrix: Texas $0.20, Oklahoma $0.19 and Arkansas $0.285 per gallon. Say your truck drove 30,000 miles and bought 5,000 gallons, so it averaged 6.0 MPG.

State	Miles	Taxable gal	Gal bought	Net gal	Tax
Texas	15,000	2,500	3,000	-500	-$100.00
Oklahoma	9,000	1,500	1,500	0	$0.00
Arkansas	6,000	1,000	500	500	$142.50

The total is $42.50 owed. Texas gives you a $100 credit because you bought more fuel there than you used, and that credit offsets most of the Arkansas tax. This is just an example to show the math, not your real return.

Surcharge states

A couple of jurisdictions add a surcharge on top of the regular rate. For 4Q2026, the IFTA matrix lists surcharges for Kentucky and Virginia. The surcharge applies to all taxable gallons used there, and you don't get credit for fuel bought there against it. The calculator adds those rows automatically.

Credits and refunds

A negative total means a credit. Depending on your base jurisdiction, a credit may be refunded or carried forward to future returns. Check your base state's rules, and remember that credits only count if you have the receipts to back them up.

Rounding rules

Jurisdictions have their own rounding and reporting conventions, such as whole miles and gallons on the return. The calculator rounds money to the cent for display. Your base state's return form has the final say, so follow its instructions when you file.

One quick sanity check: your fleet MPG should look realistic for your trucks. If it's way off, you've likely missed some miles or some fuel.

Next Steps for Filing

• Check your miles and gallons against your records before you file.
• File your return with your base jurisdiction by the deadline: April 30, July 31, October 31 or January 31.
• Keep your trip records and receipts for at least 4 years.
• Remember that you must file even in quarters with no miles.

Want this done for you? Many ELDs calculate miles by state automatically. Read our IFTA reporting guide to learn how, or use our ELD cost calculator to see what a system with built in IFTA would cost your fleet.

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Frequently Asked Questions

How is IFTA tax calculated?

Divide total miles by total gallons to get fleet MPG. For each jurisdiction, divide miles by MPG to get taxable gallons, subtract tax paid gallons bought there, and multiply by the jurisdiction's rate.

Where do IFTA tax rates come from?

IFTA, Inc. publishes a quarterly tax rate matrix with each member jurisdiction's rates. This calculator uses the quarter shown on the page.

Is this calculator my official return?

No. It is an estimate to help you plan. File your official return with your base jurisdiction using its forms and rules.

Sources

All prices, terms and registration details were checked October 2026 on the pages below. Providers change pricing often, so confirm before you buy.

• IFTA, Inc. tax rate matrix, 4Q2026
• IFTA, Inc.
• Virginia DMV IFTA tax reporting