IFTA Filing Guide for Owner-Operators (2026)
What IFTA is, who has to file, the four quarterly deadlines, and a step-by-step walkthrough of preparing your return with the 2026 rates.
What IFTA is — in plain English
The International Fuel Tax Agreement reconciles diesel taxes across the 48 contiguous US states and 10 Canadian provinces. You pay fuel tax at the pump in whichever state you fueled, then your base state collects what you owe to other states (or refunds what you overpaid) based on the miles you actually ran in each jurisdiction.
Who has to file IFTA
Any qualified motor vehicle that:
- Has a gross vehicle weight over 26,000 lbs or three or more axles, and
- Operates in two or more IFTA jurisdictions
If you only run inside one state, you don't file IFTA — you pay your home-state fuel tax at the pump and that's it.
Quarterly due dates
- Q1 (Jan–Mar): Due April 30
- Q2 (Apr–Jun): Due July 31
- Q3 (Jul–Sep): Due October 31
- Q4 (Oct–Dec): Due January 31
File even if you owe nothing — a zero return is still required.
What you need to prepare a return
- Miles driven in each jurisdiction (from your ELD or a trip log)
- Gallons of diesel purchased in each jurisdiction, with receipts showing date, location, gallons, and price
- Fleet MPG for the quarter
The math
For each jurisdiction: (miles in state ÷ fleet MPG) × state tax rate = tax owed. Subtract gallons purchased in state × state rate = tax paid at pump. The difference is what you owe (positive) or get refunded (negative). Sum across all jurisdictions for your net.
2026 rates and where to get them
Rates are republished every quarter by IFTA Inc.. The HaulerMath calculator uses the current quarter's rates.
How to actually file
Every state has its own portal (Texas Comptroller, California CDTFA, etc.). Log into your base-state portal, enter the per-jurisdiction miles and gallons, and the system computes what you owe. Pay by ACH, card, or check.
Common mistakes
- Forgetting Oregon. Oregon uses a weight-mile tax, not fuel tax. If you ran miles in OR, you owe Oregon's per-mile tax separately — IFTA shows $0 because no fuel tax was paid at OR pumps.
- Estimating gallons instead of using receipts. Auditors want receipts. Lose them and you may owe tax on every gallon claimed.
- Missing the deadline. Late filing = $50 minimum penalty plus interest. Three late returns in a row = license suspension.