IFTA and IRP / Fuel reporting
Fuel Tax in trucking
Plain-English explanation
Fuel tax is the per-gallon excise tax assessed on diesel fuel by federal and state governments, embedded in the retail pump price. Federal diesel fuel tax is 24.4 cents per gallon and applies nationally. State diesel fuel taxes vary -- from as low as $0.14 in some states to over $0.75 per gallon in others when state taxes, fees, and charges are combined. For interstate carriers, fuel taxes are administered through the International Fuel Tax Agreement (IFTA) rather than being paid separately to each state. Under IFTA, a carrier pays all fuel tax through their base state's quarterly return, which then distributes the tax revenue to each state based on miles driven there. How the IFTA calculation works: the carrier tracks total miles driven in each state and total gallons purchased in each state. The carrier calculates "miles per gallon" for the period, then determines how many gallons were "consumed" in each state based on miles driven there. If they consumed more gallons in a state than they purchased there (fueled elsewhere), they owe additional tax to that state. If they purchased more in a state than they consumed there (fueled there because prices were lower), they get a credit. Fuel tax affects carrier route planning because different states have different fuel tax rates. A carrier who fuels more in low-tax states (Oklahoma, Texas) and drives fewer loaded miles there versus high-tax states pays less net fuel tax than if they fueled and drove in equal proportion by state.
Fuel tax and registration terms usually need mileage, jurisdiction, vehicle, and date details. Keep the definition tied to the report or registration record being prepared.
Why it matters in trucking
Fuel tax is a fixed cost embedded in every gallon purchased -- it is not separately visible on most pump displays and is not optional. IFTA compliance is mandatory for carriers operating in multiple states; failure to file quarterly IFTA returns is a violation that can affect operating authority.
The office usually needs consistent mileage and fuel records before quarter-end, not after a report is already due.
Example in real use
A carrier purchases 2,000 gallons in Texas (low state fuel tax) during a quarter and drives 3,000 miles in California (high state fuel tax). At their fleet average of 6.5 mpg, they consumed 3,000/6.5 = 461 gallons in California but purchased 0 there. California fuel tax is due on 461 gallons. Texas allows a credit because the carrier purchased more in Texas than they consumed there. The IFTA return calculates the net tax owed or credited across all states.
Common mistakes or confusion
- Not tracking miles by state for IFTA -- IFTA quarterly returns require miles driven in each member jurisdiction; estimated or incomplete state mileage records produce inaccurate returns.
- Confusing fuel taxes with fuel card programs -- fuel taxes are paid regardless of which card or program is used; fuel cards reduce the per-gallon cost but do not eliminate or defer fuel tax.
- Filing IFTA late or not at all -- late IFTA returns accrue penalties and interest; persistent non-compliance can result in a suspension of IFTA credentials and operating authority.
Related terms
Related guides
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Sources and last updated
Fuel tax and registration definitions are verified against the International Fuel Tax Agreement and International Registration Plan base requirements. See the sources page.
Last updated: 2026-05-08