IFTA Fuel Tax Estimator

How IFTA works

If you run a truck across state lines, the International Fuel Tax Agreement, known as IFTA, is how fuel tax is settled between the states and Canadian provinces where you drive. Instead of filing a separate fuel tax return in every jurisdiction, you file one quarterly return with your base jurisdiction, and that return settles the tax for all of the IFTA member jurisdictions you travelled through during the quarter.

The idea behind IFTA is simple, and it surprises many new carriers: fuel tax is settled where the fuel was burned, not where it was bought. When you fill up in Texas, the tax included in the pump price is collected by Texas at the time of purchase. But if you then drive those gallons into Oklahoma, New Mexico or Louisiana, the fuel is actually being consumed there, so the tax on it belongs to those states. IFTA reconciles that difference. For each state or province, the miles you drove there are divided by your fleet average miles per gallon to work out how many gallons you burned there. That figure is multiplied by that jurisdiction's tax rate to give the tax you owe for driving there. The tax you already paid at the pump, on the gallons you bought in that state, is then credited against what you owe. If you paid more than you owed in a state, you get a credit; if you paid less, you owe the difference.

That is why the estimator above asks for three things for every state: the miles you drove there, your average miles per gallon for the quarter, and the gallons you bought there. Miles and fuel purchases rarely line up neatly, because a tank filled in one state is often burned in another, so most quarterly returns end with a mix of tax due in some states and credits in others. Add the state-by-state results together and you get your net position for the quarter: either a payment to make or a refund to claim.

What you report each quarter

Each quarterly IFTA return covers a calendar quarter, and it is based on the actual miles you ran and the actual fuel you bought in that quarter. You report the total miles travelled in each IFTA jurisdiction, including miles run on toll roads and miles run while empty, and the total gallons of taxable fuel purchased in each jurisdiction, supported by your fuel receipts. Your fleet average miles per gallon is calculated from your total miles divided by your total gallons for the quarter, and that same average is applied to every jurisdiction to work out the gallons consumed there. Use the real figures from your logs and receipts, not a guess, because the return is a tax filing and your base jurisdiction can audit it. This estimator is a planning tool: it shows you roughly where you stand before you file, so there are no surprises when the return is due.

Quarterly filing due dates

IFTA returns are filed four times a year, and the deadlines are the same every year. Missing a deadline can mean late filing penalties and interest, and repeated late filings can put your IFTA licence at risk, so put these dates in your calendar:

• Quarter 1 (January to March): due April 30
• Quarter 2 (April to June): due July 31
• Quarter 3 (July to September): due October 31
• Quarter 4 (October to December): due January 31

If a due date falls on a weekend or a public holiday, check with your base jurisdiction, as the deadline may move to the next business day. You must file a return even for a quarter in which you did not run any miles, in which case it is a zero return. Keeping your mileage and fuel records up to date through the quarter makes the filing itself a short job; leaving it all until the last week is how returns end up late or wrong.

Record-keeping duties

Good records are the foundation of IFTA, and they are a legal duty, not just good practice. For every trip you need per-state mileage records, showing where each mile was run, and you need to keep all of your fuel receipts, showing the date, the gallons purchased, the price and the place of purchase. These records must be kept for 4 years, and they must be available if your base jurisdiction audits your returns. Electronic logging devices, GPS records and fuel card reports all help, but they are a supplement to your records, not a replacement for keeping them organised: a carrier that cannot show where its miles were run or where its fuel was bought can lose credits it was entitled to and can be assessed on estimated figures instead. File your receipts by month as the quarter goes on, reconcile them against your mileage at the end of each month, and keep a copy of every quarterly return you file.

A note on tax rates

State diesel tax rates change quarterly, and each IFTA jurisdiction sets its own rate, so the rates used by any estimator go out of date. The rates embedded in the tool above are approximate and are there to give you a realistic estimate, not a filing figure. Before you file a return, always check the current rates for the quarter and the jurisdictions concerned and verify them at iftach.org, the official IFTA website. If you are just starting out and still working out which registrations you need, try our Texas Trucking Authority Checker, and see all of our free calculators and checkers on the Trucking Tools hub.

Frequently asked questions

What is IFTA?

IFTA is the International Fuel Tax Agreement. It is an agreement between the US states (except Alaska and Hawaii) and the Canadian provinces that lets a carrier file one quarterly fuel tax return with its base jurisdiction instead of a separate return in every state or province it drove through. That one return settles fuel tax across all member jurisdictions, based on the miles driven and the fuel bought in each one.

When are IFTA returns due?

IFTA returns are due four times a year: the first quarter return is due April 30, the second quarter return is due July 31, the third quarter return is due October 31, and the fourth quarter return is due January 31. A return must be filed even if you ran no miles in the quarter.

What records do I have to keep for IFTA?

You must keep per-state mileage records showing the miles driven in each jurisdiction and all of your fuel receipts showing the gallons bought, the date and the place of purchase. These records must be retained for 4 years and made available for audit.

Why can I owe tax in a state where I bought plenty of fuel?

Because tax follows consumption, not purchase. You are taxed on the fuel you burned in a state, worked out from the miles you drove there, and credited for the tax you paid on the fuel you bought there. If you drove more miles in a state than the gallons you bought there can cover, you owe the difference, however much fuel you bought; if you bought more than you burned there, you get a credit.