IFTA Filing Guide for Small Carriers (2026)

What is IFTA?

The International Fuel Tax Agreement (IFTA) is a tax agreement between the 48 contiguous US states and 10 Canadian provinces. If you operate commercial vehicles across state lines, you need to file IFTA quarterly to report fuel purchased and miles driven in each jurisdiction.

In plain English: IFTA makes sure you pay the right amount of fuel tax to each state based on how many miles you actually drove there, not just where you bought fuel.

Who needs to file IFTA?

You need an IFTA license if your vehicle has two axles and a gross vehicle weight or registered gross vehicle weight exceeding 26,000 lbs (11,797 kg), or has three or more axles regardless of weight, or is used in combination when the combined weight exceeds 26,000 lbs. The vehicle must travel in at least two IFTA jurisdictions.

If you're an owner-operator running a single truck across state lines, that's you.

2026 IFTA Filing Deadlines

Late filings can result in penalties of $50 or more per month, plus interest on unpaid taxes. Some states add their own penalties on top.

How to calculate IFTA (step by step)

1. Track miles by state. Record every mile driven in each jurisdiction. GPS or odometer readings at each state line.
2. Track fuel by state. Record every fuel purchase: date, state, gallons, and cost. Keep receipts.
3. Calculate total MPG. Total miles driven (all states) divided by total gallons purchased (all states).
4. Calculate taxable gallons per state. Miles in each state divided by your fleet MPG = gallons "consumed" in that state.
5. Compare to fuel purchased per state. If you consumed more than you bought in a state, you owe that state. If you bought more than you consumed, you get a credit.
6. Apply tax rates. Multiply the net gallons (owed or credited) by each state's fuel tax rate.

Common IFTA mistakes that trigger audits

• Missing or unreadable fuel receipts
• Not tracking miles in states where you didn't buy fuel
• Mixing personal and business miles
• Using estimated MPG instead of actual calculations
• Filing late consistently (states flag repeat offenders)
• Forgetting toll-road miles count as jurisdictional miles

How to automate IFTA filing

The biggest pain in IFTA is data collection. If your drivers are saving paper fuel receipts and you're adding them up at the end of the quarter, you're spending a full weekend on something software can do automatically.

Fleet management software like FleetKit Fuel lets drivers log fuel from their phone at the pump. Every entry is tagged with date, state, gallons, and cost. At the end of the quarter, your IFTA totals are already calculated — you just export and file.

For small carriers (1-50 trucks), dedicated IFTA software like WEX charges $15-20 per vehicle per month. FleetKit includes fuel tracking and IFTA calculations as part of the $99/month Pro plan for up to 25 trucks — along with 6 other fleet management apps.