IFTA fuel tax: what it is, who must file, and how the quarterly return works
By TruePermitReviewed by the TruePermit compliance teamUpdated
The International Fuel Tax Agreement (IFTA) lets a carrier operating a qualified motor vehicle across two or more of its 58 member jurisdictions — the 48 contiguous US states and 10 Canadian provinces — file a single quarterly fuel-tax return with its base jurisdiction instead of a separate return in every state. You report miles and fuel by jurisdiction, and the return nets out what you owe or are credited in each.
What is IFTA?
IFTA is an agreement among the 48 contiguous US states and the 10 Canadian provinces that simplifies fuel-tax reporting for interstate carriers. Your base jurisdiction issues one IFTA license and a set of decals for each qualified vehicle. Each quarter you file one return covering every member jurisdiction, and your base jurisdiction distributes the tax to the others.
Who must file IFTA?
IFTA applies to carriers operating a qualified motor vehiclein two or more member jurisdictions. A vehicle is generally qualified if it has a gross weight over 26,000 pounds or has three or more axles regardless of weight. Carriers running only within one jurisdiction, or only in non-IFTA areas, don't file an IFTA return.
How is the IFTA tax calculated?
For each jurisdiction you compute taxable gallons — your taxable miles there divided by your fleet's average miles-per-gallon — and multiply by that jurisdiction's tax rate. You then subtract the tax you already paid at the pump on fuel purchased in that jurisdiction. The result is a net amount owed (or a credit) per jurisdiction, and the return sums them into a single balance. Some jurisdictions add a surcharge. Rates come from the official quarterly IFTA matrix, which changes every quarter — so figures are always tied to a specific period.
When are IFTA returns due?
IFTA returns are filed quarterly and are generally due the last day of the month after each quarter ends: April 30 (Q1), July 31 (Q2), October 31 (Q3), and January 31 (Q4). You must file every quarter you hold a license — even one with zero miles — and keep your mileage and fuel records, because IFTA accounts are audited.
IFTA vs. IRP — what's the difference?
Both use per-jurisdiction mileage, but they're separate. IFTA is fuel tax — a quarterly return. IRP is registration — the apportioned plate that lets you operate interstate. You generally need both. See our IRP guide.
What happens if you file late or wrong?
Late or unfiled returns draw penalties and interest, and your IFTA license can be suspended — which jeopardizes your ability to run interstate. Because IFTA is audited, underreported miles or unsupported fuel credits surface later as assessments plus penalties.
TruePermit builds your IFTA return for you
Your trips and fuel become a filed-ready IFTA return across every jurisdiction — taxable gallons, net tax, and credits computed on the official quarterly matrix and reconciled to your odometers. The AI Copilot explains the numbers; the engine computes them. Free for one truck to start.
Start freeThis guide is general information for compliance planning — not legal or tax advice. Rates change every quarter; verify against the official IFTA matrix and your base jurisdiction before filing.