Free calculator
Fleet MPG calculator for IFTA
Type each truck's miles and gallons for the quarter. The IFTA return uses one MPG per fuel type: all miles divided by all gallons, to two decimals, not the average of the trucks' MPG.
Sample data: two made-up trucks. Type your own odometer miles and fuel gallons for the quarter.
Same fuel type only: a return has one MPG per fuel type. Your numbers stay in this browser.
Result
- Fleet MPG for the return
- 6.58
- Total miles
- 43,600 mi
- Total gallons
- 6,630 gal
- Truck 101
- 6.41 MPG
- Truck 102
- 7.05 MPG
The plain average of the trucks' MPG is 6.73, not 6.58: the return divides total miles by total gallons, so a truck that drives more weighs more. Type 6.58 in the IFTA calculator.
Filing this quarter? Pro prints the worksheet.
Every jurisdiction line with its rate, the totals and the MPG on one printable sheet, an Excel file with live formulas and trip and fuel logs for next quarter.
How it works
Fleet MPG = total miles / total gallons, rounded to 2 decimals. The same MPG turns every jurisdiction's taxable miles into taxable gallons, so it has to be consistent across the return: miles and gallons for the same trucks, the same fuel type and the same dates.
Sample data: Truck 101 drives 31,200 miles on 4,870 gallons (6.41 MPG) and Truck 102 drives 12,400 miles on 1,760 gallons (7.05 MPG). The fleet MPG is 6.58; the plain average of the two would be 6.73, which overweights the truck that drove less.
Sources of the rules
- MPG to two decimals: IFTA Procedures Manual (effective January 2026), P720.350 "Average fuel consumption factor (to two decimal places)" — https://www.iftach.org/manuals/2026/PM/Procedures%20Manual%20-%2001-01-26.pdf, read on 2026-09-29
- Taxable gallons from MPG: Virginia DMV, RDT 121-I IFTA Quarterly Tax Return Instructions, Section 7 column D and Section 8 column E — https://www.dmv.virginia.gov/sites/default/files/forms/rdt121i.pdf, read on 2026-09-29
Frequently asked questions
- How do I calculate MPG for IFTA?
- Add the miles of every qualified truck in every jurisdiction for the quarter, add all the gallons put in those trucks (tax-paid or not), and divide miles by gallons. Round to two decimals.
- Why not average each truck's MPG?
- Because the trucks drive different distances. In the sample, the average of the two trucks is 6.73 but the fleet burns 6.58 miles per gallon overall; only the total-over-total figure makes the taxable gallons add up to the fuel you used.
- What MPG is normal for a semi truck?
- This site does not publish a benchmark. Use the MPG your own miles and fuel receipts give; an unusually low or high figure is something your base jurisdiction may ask you to explain, so check the records behind it.
- Where do I use the fleet MPG?
- Type it in the MPG field of the IFTA calculator, or leave that field empty and the calculator divides the total miles by the total gallons you entered there.
Guides
- What records do you need to keep for IFTA?
The trip and fuel receipt fields the IFTA Procedures Manual lists, how long to keep them (four years) and why the MPG on the return must match them.