IFTA fuel tax basics for truck drivers

IFTA, the International Fuel Tax Agreement, lets a carrier report fuel tax for every member jurisdiction on one quarterly return filed with its base jurisdiction. If your truck is a qualified motor vehicle and it crosses state lines, you need an IFTA license and you file four returns a year, each backed by mileage and fuel records. The return comes down to one idea: each jurisdiction collects tax on the fuel you burned on its roads, minus the tax you already paid at its pumps.

This guide is general information, not tax or legal advice; your base jurisdiction's rules and instructions control.

Who needs an IFTA license

The IFTA Articles of Agreement define a qualified motor vehicle as one used, designed or maintained to transport people or property that meets any of these tests:

• Two axles and a gross vehicle weight or registered gross vehicle weight over 26,000 pounds (11,797 kilograms)
• Three or more axles, regardless of weight
• Used in combination, when the combination's gross or registered gross weight is over 26,000 pounds

The axle tests look at the power unit only. IFTA's board has interpreted the definition so that trailer axles don't count, which means a two-axle truck pulling a trailer at a combined 26,000 pounds or less is not a qualified motor vehicle. Recreational vehicles used only for personal pleasure are excluded.

If you run a qualified vehicle in two or more member jurisdictions, you need an IFTA license from your base jurisdiction, which also issues annual decals for each truck. Some jurisdictions offer fuel tax trip permits for an occasional trip instead, so ask before a one-time run. If you're leased onto a carrier, read your lease: it decides whether you or the carrier holds the license and files.

Quarterly filing deadlines

IFTA runs on calendar quarters. Each return covers one quarter's miles and fuel and is due on the last day of the month after the quarter ends.

When a due date falls on a weekend or legal holiday, the return is due the next business day. January 31, 2027 is a Sunday, for example, so the fourth-quarter 2026 return is due Monday, February 1, 2027; confirm the date with your base jurisdiction.

A licensed carrier files every quarter, even a quarter with no miles. Michigan's IFTA office, for one, tells licensees that a return is required with no activity and that missing returns lead to assessments the state computes on its own. Late returns also bring penalties and interest.

How the return works

The return doesn't tax fuel where you bought it. It figures how much fuel you burned in each jurisdiction, applies that jurisdiction's rate, and credits the tax you already paid at the pump there. Each fuel type is reported separately. For diesel, the steps look like this:

1. Total your miles for the quarter: every mile the truck ran, taxable or not.
2. Total the gallons you put in the truck during the quarter.
3. Divide miles by gallons to get your average miles per gallon (MPG).
4. For each jurisdiction, divide its taxable miles by your MPG. That's the fuel you're treated as having burned there.
5. Subtract the tax-paid gallons you bought in that jurisdiction to get net taxable gallons.
6. Multiply net taxable gallons by that jurisdiction's rate for the quarter. A positive number is tax due; a negative number is a credit.
7. Add up every jurisdiction's line. The total is what you pay your base jurisdiction, or the credit it owes you.

Rates change, so use the tax rate matrix IFTA, Inc. publishes for the quarter you are filing, never last quarter's.

A worked example

All numbers in this example are made up for illustration, including the tax rates. Real rates come from the current quarter's matrix.

Say one truck ran 30,000 miles in four states during a quarter and bought 5,000 gallons of tax-paid diesel. Its average is 30,000 ÷ 5,000 = 6.0 MPG.

Add the lines: $360.00 + $275.00 - $240.00 - $150.00 = $245.00 owed to the base jurisdiction.

The truck bought exactly as many gallons as it burned and still owes $245. It fueled heavily in States A and C, where the example rates are low, and ran many of its miles in States B and D, where they're higher. That's how IFTA is designed: fueling in a low-tax state doesn't reduce the tax owed on miles you drive in other states.

Records to keep

IFTA requires distance records for each vehicle. State IFTA offices accept an individual vehicle mileage record (IVMR) or trip report showing:

• Beginning and ending dates of each trip
• Origin and destination, including city and state
• Routes of travel
• Beginning and ending odometer, hubodometer or engine control module readings
• Total trip distance and the distance in each jurisdiction
• The vehicle unit number and the licensee's name

Every mile belongs on the record, including empty, deadhead and bobtail miles.

For fuel, keep a receipt for every purchase showing the date, the seller's name and address, gallons, fuel type, price per gallon or total sale, the unit number and the purchaser's name. Receipts with alterations or erasures aren't accepted for credit.

Keep everything for four years from the return's due date or the date you filed, whichever is later, and produce it when any member jurisdiction asks. If your records can't support the return, an auditor can assess tax using a standard of 4 miles per gallon, as the Illinois Department of Revenue's IFTA recordkeeping guide spells out.

Common mistakes

• Rebuilding state miles from memory at the end of the quarter instead of recording them trip by trip
• Leaving deadhead or bobtail miles off the trip sheets
• Losing fuel receipts, which costs you the credit for tax you already paid at the pump
• Filing with an old rate matrix
• Skipping a return because the truck sat all quarter

How Fort Route helps with the worksheet

Fort Route's IFTA and receipt tools are a worksheet aid, not a filing service. While you navigate with the app, it logs miles by state from GPS, and you can also add miles from a planned route. State lines come from simplified borders, accurate to about a kilometer, and miles driven with the app closed aren't captured, so check the totals against your odometer and trip records before you file.

To log fuel, you photograph the receipt and the app reads it on your phone, pulling out the gallons, price, total, date, state and truck stop for you to confirm or correct. The receipt photos stay on your phone. At the end of the quarter, the worksheet applies the IFTA rate matrix and exports a CSV file or a printable PDF you can hand to your preparer or use to fill in your base jurisdiction's return. If you also track meal days, see the per diem guide.