IFTA, Explained Without the Jargon
The most misunderstood filing in trucking, because it looks like a tax and behaves like a settlement. You already paid the tax at the pump. The return decides which states keep it.
What it is actually doing
Every state and province charges fuel tax to pay for its roads. Without an agreement, a carrier crossing six states would file with six authorities. The International Fuel Tax Agreement replaces that with one licence, one return and one payment to your base jurisdiction, which then distributes the money to the others.
Here is the part that confuses everyone: you pay the tax when you buy diesel, in whichever state you buy it. The quarterly return reconciles what you paid in each state against what you owe each state based on the miles you drove there.
Which is why the return can hand you a bill even though you paid tax on every gallon. Buy cheap fuel in a low-tax state and drive the miles in a high-tax one, and you owe the difference. It is not a penalty and it is not an error; it is the agreement working exactly as designed.
Who needs a licence
A qualified motor vehicle used, designed or maintained to transport persons or property, operated across jurisdiction lines, being one that:
- has two axles and a gross or registered gross vehicle weight over 26,000 pounds, or
- has three or more axles regardless of weight, or
- is used in a combination whose weight exceeds 26,000 pounds.
Note that three axles qualifies you on axle count alone. Some hotshot and specialised configurations fall in on that basis when the operator assumed weight kept them out. Recreational vehicles are excluded by the definition.
You license in your base jurisdiction: the member jurisdiction where the vehicles are based for registration, where operational control and records are kept, and where the fleet accrues some travel. For a one-truck operator that is normally the home state.
How the return works, worked through
The calculation is the same in every jurisdiction. The example below uses the diesel rates published for the third quarter of 2026 (July–September); rates change, so take your own from the current IFTA rate matrix for the quarter you are filing.
A one-truck carrier runs 15,000 miles in the quarter across four states and buys 2,500 gallons: 1,000 in Indiana and 1,500 in Missouri.
- Fleet average MPG. Total miles ÷ total gallons: 15,000 ÷ 2,500 = 6.00. Every mile counts, including empty and personal miles, and every gallon you put in the truck.
- Taxable gallons per state. Miles in each state ÷ 6.00.
- Tax due per state. Taxable gallons × that state’s rate.
- Tax already paid per state. Gallons bought there × the same rate.
- Net. Due minus paid. Positive is owed; negative is a credit.
| State | Miles | Taxable gal. | Rate | Tax due | Gal. bought | Tax paid | Net |
|---|---|---|---|---|---|---|---|
| Ohio | 3,000 | 500.00 | $0.470 | $235.00 | 0 | $0.00 | +$235.00 |
| Indiana | 4,000 | 666.67 | $0.630 | $420.00 | 1,000 | $630.00 | −$210.00 |
| Illinois | 5,000 | 833.33 | $0.738 | $615.00 | 0 | $0.00 | +$615.00 |
| Missouri | 3,000 | 500.00 | $0.295 | $147.50 | 1,500 | $442.50 | −$295.00 |
| Total | 15,000 | 2,500.00 | $1,417.50 | 2,500 | $1,072.50 | +$345.00 |
The carrier paid $1,072.50 in fuel tax at the pump and still owes $345.00, because most of the fuel was bought in Missouri and Indiana and most of the miles were run in Illinois and Ohio. The Missouri and Indiana credits are not refunded separately; they offset the Ohio and Illinois balances on the same return. Had the truck fuelled in Illinois instead, the return would have come out close to zero — but the total tax over the quarter would have been the same.
Some jurisdictions also levy a surcharge reported as a separate line. In 3Q 2026 the matrix showed diesel surcharges of $0.105 a gallon in Kentucky and $0.143 in Virginia. Check the matrix for the jurisdictions you ran in, because a surcharge line is easy to miss.
When the return is due
Quarterly, on the last day of the month following the end of the calendar quarter. If that falls on a weekend or holiday, it moves to the next business day.
| Quarter | Period | Return due |
|---|---|---|
| Q1 | January – March | 30 April |
| Q2 | April – June | 31 July |
| Q3 | July – September | 31 October |
| Q4 | October – December | 31 January |
A return is due even in a quarter where you did not run. Filing zero is required; filing nothing is a violation.
What you have to record
The return needs two things per jurisdiction: miles driven and fuel purchased. So the underlying records are:
- Trip records for each vehicle: start and end dates, origin and destination, route, beginning and ending odometer or ECM readings, total distance, distance in each jurisdiction, and the unit number or VIN.
- Every fuel receipt, showing date, seller’s name and address, gallons, fuel type, price, the vehicle it went into and the purchaser’s name. A credit card statement without itemised purchases is not enough.
Keep them for four years from the return’s due date or filing date, whichever is later. A pending refund request extends that until the refund is made or denied. IFTA has no 100- or 150-mile radius exemption from these records, unlike the hours-of-service rules.
Most ELD and fleet systems produce the mileage breakdown automatically, which is the single biggest time saving available here. If you are doing it by hand, do it weekly — reconstructing a quarter of state-line crossings from memory in the last week of the month is how errors and late filings happen.
Licence and decals
- The base jurisdiction issues one licence and two decals per vehicle, displayed on the exterior of both sides of the cab.
- The licence runs for the calendar year. Renewing carriers get a grace period through January and February to display the new decals.
- A 30-day temporary decal permit can be issued for a specific vehicle, for example while new decals are on the way. It replaces the decals, not the licence.
What late filing costs
The penalty is set by the agreement itself, so it is the same across member jurisdictions: the base jurisdiction may assess $50 or 10 percent of the delinquent taxes, whichever is greater, for failing to file, filing late or underpaying. Texas, which publishes it in exactly those terms, is one example. Jurisdictions can add other penalties under their own law.
Interest is separate. For US carriers it runs at two percentage points above the IRS underpayment rate, reset each January and charged monthly, calculated for each jurisdiction you owe.
The larger risk is not the penalty. Persistent non-filing gets your IFTA licence revoked, and without it you cannot legally run those vehicles interstate.
Common mistakes
- Leaving out miles. Deadhead, bobtail and personal miles all go into total miles and the MPG. Dropping them inflates MPG and understates tax in every state.
- Missing receipts. No qualifying receipt, no credit for that fuel, so you pay the tax twice.
- Fuel with no matching miles. Every gallon put in the truck belongs on the return, including fuel bought in a state you only passed through.
- Using last quarter’s rates. Rates change quarterly.
- Letting credits sit. Credits carry forward for a limited time — eight quarters under the agreement — and you can ask your base jurisdiction to refund accumulated credits instead.
How it interacts with everything else
IFTA is separate from IRP apportioned plates, from the UCR registration, and from the Form 2290 heavy vehicle use tax. Four different obligations, four different administrators, four different calendars. The full picture is in the compliance calendar.
Frequently asked questions
Do I need IFTA for one truck?
If it is a qualified motor vehicle crossing jurisdiction lines, yes. The number of trucks is irrelevant.
Why do I owe money when I paid tax at the pump?
Because tax is paid where fuel is bought and owed where miles are driven. Buying in a low-tax state and driving in a high-tax one produces a balance due.
Do I file if I did not run that quarter?
Yes. A zero return is still a return.
Does a three-axle vehicle need IFTA even if it is light?
Yes. Three or more axles qualifies on axle count alone, regardless of weight.
How long do I keep IFTA records?
Four years from the return’s due date or filing date, whichever is later.
Related
Sources
- International Fuel Tax Agreement — Texas Comptroller, as an example of a base jurisdiction’s published rules.
- International Fuel Tax Association.
- IFTA Articles of Agreement (R212, R245, R605–R660, R930–R960, R1120, R1220, R1230) — International Fuel Tax Association.
- IFTA-105, 3rd Quarter 2026 fuel tax rates — New York State Department of Taxation and Finance, reproducing the IFTA rate matrix.
- IFTA Record Keeping Requirements — Iowa DOT, as an example of a base jurisdiction’s published rules.
General information, not legal advice. Regulations change; confirm current requirements with the agency before acting.