RouteAllIFTA Mileage for Oversize Haulers
Last verified September 8, 2026 against the IFTA Articles of Agreement and Procedures Manual linked below.
IFTA is the International Fuel Tax Agreement. It splits the fuel tax you already paid among the states you actually drove through. Your oversize permit does not change what you owe, but it does change your route, and the route is what IFTA taxes.
Every rule below is quoted from IFTA's own published manuals, so you can check each one at source.
In one minute: IFTA is a quarterly report of where your miles happened. You report every mile in every jurisdiction, and every gallon you bought. The agreement then moves your fuel tax to the states that carried the miles.
- Permit routes are usually longer than the direct route, and those extra miles are reportable.
- Detours count as miles too, in whichever jurisdiction they happened.
- Your permit names the roads, which is also the record of where you drove.
- Permit thresholds are a separate question, covered in do you need an oversize permit? The 4 numbers that decide.
The oversize part of this is simple. A permit route puts miles in places a direct route would not, and those miles still belong on the return.
Which trucks are covered by IFTA?
A qualified motor vehicle is one that hauls persons or property and meets a size test. IFTA sets that test three ways, and meeting any one of them is enough. Two axles over 26,000 pounds qualifies. Three or more axles qualifies at any weight at all.
"Qualified Motor Vehicle means a motor vehicle used, designed, or maintained for transportation of persons or property and: .100 Having two axles and a gross vehicle weight or registered gross vehicle weight exceeding 26,000 pounds or 11,797 kilograms; or .200 Having three or more axles regardless of weight; or .300 Is used in combination, when the weight of such combination exceeds 26,000 pounds or 11,797 kilograms gross vehicle or registered gross vehicle weight."
— IFTA Articles of Agreement R245. Verified September 8, 2026.
That middle line catches most heavy haul equipment. A three-axle tractor is qualified whatever it weighs. Recreational vehicles are excluded by the same section.
What counts as total distance?
Total distance means all of it, with no exceptions for empty running. IFTA defines it as every mile travelled in the quarter by every qualified vehicle in your fleet, without regard to whether a jurisdiction calls those miles taxable. Deadhead miles count. Permit detour miles count.
"Total Distance means all miles or kilometers traveled during the tax reporting period by every qualified vehicle in the licensee's fleet, regardless of whether the miles or kilometers are considered taxable or nontaxable by a jurisdiction."
— IFTA Articles of Agreement R266. Verified September 8, 2026.
Total distance and taxable distance are two different numbers. A jurisdiction may allow you to deduct exempt miles from its total to reach its taxable figure, but the mile still gets reported first.
Miles run under a trip permit work the same way. They belong in total distance, and in that jurisdiction's total, without becoming taxable miles there.
What has to be in a mileage record?
A manual distance record needs seven elements before a base jurisdiction must accept it. IFTA lists them in the Procedures Manual, and route of travel is one of them. That single element is where an oversize permit and an IFTA record meet.
The seven elements of a manual record, per Procedures Manual P540.100:
- Beginning and ending dates of the trip the record covers.
- Origin and destination of the trip.
- Route of travel.
- Beginning and ending odometer, hubodometer or engine control module reading.
- Total distance of the trip.
- Distance travelled in each jurisdiction during the trip.
- Vehicle identification number or unit number.
A GPS-produced record has its own list under P540.200, which also requires the route of the vehicle's travel plus the original location data and the reading interval.
How does an oversize permit affect your miles?
A permit route is rarely the shortest route. The state routes you around a low bridge or a restricted road, which adds miles in that jurisdiction and sometimes moves miles into another one. Those are real miles and they belong on the return.
Two habits keep the numbers straight:
- Record the permitted route, not the route you would have driven unpermitted.
- Log the detour in the jurisdiction where it actually happened.
- Escort miles follow the same route, and pilot car requirements by state sets out when you need one.
Leaving the permitted route creates a second problem on top of the IFTA one. Our guide on what happens if you leave your permitted route covers the enforcement side.
Do not report the direct-route mileage when you drove a permitted detour. The route of travel is an audited element of the record.
When is the IFTA return due?
The return and full payment are due on the last day of the month after the quarter closes. If that day is a Saturday, a Sunday or a legal holiday, the due date moves to the next business day. A return not filed by the due date is late and the tax is delinquent.
"The tax return and full payment of taxes shall be due on the last day of the month following the close of the reporting period for which the tax return is due."
— IFTA Articles of Agreement R960.100. Verified September 8, 2026.
The four quarterly deadlines are April 30, July 31, October 31 and January 31. They are stated here in prose so a listener gets them too. The table below repeats them alongside the months each one covers.
| Quarter | Months covered | Return due |
|---|---|---|
| First | January, February, March | April 30 |
| Second | April, May, June | July 31 |
| Third | July, August, September | October 31 |
| Fourth | October, November, December | January 31 |
Each date shifts to the next business day when it lands on a weekend or a legal holiday. That is the only relief IFTA gives on the deadline itself.
How long do you keep the records?
Four years, counted from the later of two dates. IFTA measures from the date the return was due, or the date you actually filed it, whichever falls later. A waiver or a jeopardy assessment extends the period further still. The clock therefore runs well past the quarter the miles belong to.
"A licensee shall retain the records of its operations to which IFTA reporting requirements apply for a period of four years following the date the IFTA tax return for such operations was due or was filed, whichever is later, plus any period covered by waivers or jeopardy assessments."
— IFTA Procedures Manual P510. Verified September 8, 2026.
Permits are part of that paperwork in practice, because the permit proves the route of travel you reported. Keep the permit with the trip record for the same four years.
IFTA checks before you roll
Log the route you were permitted to drive, in the jurisdiction where each mile happened, and keep the permit with the trip. Total distance means every mile, taxable or not, so a permitted detour is reportable rather than optional. If you are still working out permit thresholds, the RouteAll driver guides cover that side, and RouteAll support: report a permit the app read wrong handles app issues.
Common questions
Does an oversize permit change what I owe under IFTA?
No. The permit does not change the tax, but it changes the route, and the route is what IFTA measures. A permitted detour puts miles in a jurisdiction the direct route may have missed. Report the miles where they were actually driven.
Do permitted detour miles count as total distance?
Yes. IFTA defines total distance as all miles travelled by every qualified vehicle in the fleet, regardless of whether a jurisdiction treats them as taxable. A detour the state routed you onto is a real mile. It belongs on the return.
How long must I keep my mileage records?
Four years, from the later of the date the return was due or the date you filed it, plus any period covered by a waiver or jeopardy assessment. Keep the permit alongside the trip record, because the permit evidences the route of travel you reported.
Does RouteAll file IFTA returns for me?
No. RouteAll reads the permit you already hold and turns the roads on it into navigation. It does not file IFTA returns, calculate fuel tax, issue permits, or guarantee compliance. The driver and the licensee remain responsible for the records.
Further reading
Sources
- IFTA, Inc., IFTA Articles of Agreement, sections R245, R266, R960 and R970.
- IFTA, Inc., IFTA Procedures Manual, sections P510, P540 and P920.
- IFTA, Inc., IFTA governing manuals index, for the current effective versions.
- IFTA, Inc., Carrier information, on contacting your base jurisdiction.
RouteAll reads the permit you provide. It does not issue permits or guarantee compliance. The driver remains responsible for the load. This guide is written from IFTA's published governing documents and is not tax advice; your base jurisdiction administers your account and its rules govern. Rules change; verify before filing.