IFTA quarterly fuel tax filing deadlines fall on April 30, July 31, October 31, and January 31 — one month after each calendar quarter closes. When a due date lands on a weekend or legal holiday, the return is timely if it is submitted on the next business day. The Q4 2025 return, for instance, was technically due January 31, 2026, but because that Saturday pushed the deadline forward, filings postmarked or transmitted by Monday, February 2, 2026, were on time.1International Fuel Tax Association. Carrier Information
The Four Quarterly Deadlines
- Q1 (January through March): due April 30
- Q2 (April through June): due July 31
- Q3 (July through September): due October 31
- Q4 (October through December): due January 31
A return is required every quarter, without exception. If your qualified vehicles ran zero miles during the period, you still file a zero-activity return. Skipping a quarter because the trucks sat idle is one of the quickest routes to a suspended IFTA license.
What Goes on the Return
The return reconciles what you burned in each jurisdiction against what you paid at the pump there. The math runs in four steps.
Fleet Average MPG
Add every mile your qualified vehicles drove during the quarter, including deadhead, bobtail, and off-highway miles. Then add every gallon put into those vehicles’ tanks over the same period, whether from a retail pump or your own bulk storage. Divide total miles by total gallons and round to two decimal places. That figure is your fleet MPG for the quarter.
Taxable Gallons by Jurisdiction
For each jurisdiction you drove in, divide the taxable miles there by your fleet MPG, then round to the nearest whole gallon. Some jurisdictions allow certain miles to be excluded — travel on private roads, for example — so review the IFTA distance exemption tables before you calculate.2International Fuel Tax Association. IFTA Distance Exemptions
Tax Owed, Tax Paid, and Surcharges
Multiply each jurisdiction’s taxable gallons by its fuel tax rate for the quarter you are filing. Rates change quarterly, and the IFTA, Inc. tax rate matrix is the authoritative source.3International Fuel Tax Association. IFTA Tax Rates Subtract the tax-paid gallons you bought at the pump in that jurisdiction. If you bought more than you burned there, the difference is a credit; if you burned more than you bought, it is additional tax due.
Indiana, Kentucky, and Virginia each impose a diesel surcharge on top of the base rate, and that surcharge is calculated on a separate line.4International Fuel Tax Association. Tax Rate Matrix Different fuel types — diesel, gasoline, propane, natural gas — go on separate lines because each has its own rate.
Net the Quarter
Add the tax owed and credits across every jurisdiction. The total is either your net payment for the quarter or a net refund. A net credit is possible when you fuel heavily in high-tax states and drive mostly through low-tax ones, but a balance due is the more common outcome.
Records That Support the Return
Every number on the return has to be backed by documentation. The records split into distance and fuel.
Distance records need to show every mile driven, broken out by jurisdiction. Daily trip sheets, driver logs, and GPS-equipped ELDs are all acceptable. If you rely on an ELD or GPS system, it should capture location data at least every 60 minutes or at each change of duty status, along with odometer or ECM readings at the start and end of each trip. There is no official IFTA certification for ELDs, so confirming that your system captures jurisdiction-by-jurisdiction distance accurately is on you.
Fuel records need a receipt or invoice for every purchase, showing seven items: the date, the seller’s name and address, gallons purchased, fuel type, price per gallon or total paid, the qualified vehicle that received the fuel, and the purchaser’s name.5International Fuel Tax Association. International Fuel Tax Agreement Procedures Manual A vendor code can substitute for the seller’s full address if the code can be cross-referenced. Bulk fuel drawn from your own tanks also has to be documented.
Keep everything — distance logs, fuel receipts, trip sheets, summary documents — for at least four years from the return’s due date or filing date, whichever is later.5International Fuel Tax Association. International Fuel Tax Agreement Procedures Manual Any member jurisdiction can request them for audit, not only your base jurisdiction. If the records are inadequate, the auditor can estimate your fuel consumption from industry averages, distributor data, or comparable carriers. When no such source is available, the default assumption is 4 miles per gallon, which is well below what most modern trucks achieve and will inflate the tax owed. Any pump credits you cannot support with receipts are disallowed.
How to File and Pay
Filing runs through your base jurisdiction. Most operate a secure online carrier portal that validates the calculations as you enter them, and online filing is the default expectation in most states. Paper filing is still accepted, particularly where electronic filing is not available. Payment goes with the return: electronic funds transfer or credit card for online filers, check or money order for paper filers. If you mail a return, use certified mail so the postmark date is documented, and keep the confirmation number or stamped receipt as proof that the jurisdiction accepted the filing.
What Late Filing Costs
Miss a deadline and the penalty is $50 or 10 percent of the delinquent tax, whichever is greater. It applies whether you file a day late or never, and it applies to underpayments too.6International Fuel Tax Association. International Fuel Tax Agreement Articles of Agreement The base jurisdiction keeps the penalty; it is not distributed to the others. Base jurisdictions can also add penalties under their own state laws, so treat the IFTA figure as a floor.
Interest is separate and compounds monthly. For U.S. carriers, the annual rate is set at two percentage points above the IRS underpayment rate under Internal Revenue Code Section 6621(a)(2), adjusted each January 1. Monthly interest is one-twelfth of that rate, calculated separately for each jurisdiction you owe, running from the original due date. A partial month counts as a full month.6International Fuel Tax Association. International Fuel Tax Agreement Articles of Agreement Because interest runs in every jurisdiction where a balance sits, small amounts left unpaid compound faster than they look on any single line.
Missed returns, unpaid tax, and inadequate records can also lead to suspension or revocation of the IFTA license.7International Fuel Tax Association. International Fuel Tax Agreement Articles of Agreement – License Revocation and Reinstatement Within 10 days of any suspension, every other member jurisdiction is notified through the clearinghouse, so weigh station officers anywhere in the country can see the status. Reinstatement can require a fee and a fuel tax bond sized to potential liability across all jurisdictions.
Annual License Renewal Runs Alongside the Quarterly Filings
IFTA credentials are valid for one calendar year, January 1 through December 31, and must be renewed each year. Renewal usually requires that all quarterly returns through at least the third quarter are filed and paid, along with an updated equipment list showing each vehicle’s year, make, VIN, and registration details. Decal fees vary — some jurisdictions charge nothing, others a small per-vehicle amount. An unpaid Unified Carrier Registration fee can delay renewal or trigger a suspension, so keep both accounts current.