IFTA fuel tax calculator
Enter the miles you drove and the fuel you bought in each jurisdiction this quarter, plus each rate from the IFTA matrix. You get your MPG, tax due or credit per jurisdiction and the net.
Updated October 2026 · Free, no signup
One row per jurisdiction you drove in this quarter. Enter each tax rate from the IFTA quarterly tax rate matrix for the quarter you're filing.
IFTA quarter estimate
- Total miles
- 10,000
- Total gallons
- 2,000
- Fleet MPG
- 5.00
- State 1: +700 net gal
- $0.00
- State 2: -700 net gal
- $0.00
- Net tax due
- $0.00
Some rates are 0. Enter each jurisdiction's rate from the current IFTA matrix for a real number.
Estimate only. Your base jurisdiction's return is the official filing; some jurisdictions add surcharges listed separately on the matrix.
10,000 miles across 2 jurisdictions this quarter. Our dispatchers plan each route to keep empty miles down, and you confirm every load before it's booked.
Plan my next loadsHow the calculator works
IFTA lets an interstate carrier file one fuel tax return with its base jurisdiction instead of one in every state. The return reconciles where you drove with where you bought fuel.
| Step | Formula |
|---|---|
| Fleet MPG | Total miles / total gallons, all jurisdictions |
| Taxable gallons | Miles in the jurisdiction / fleet MPG |
| Net gallons | Taxable gallons - tax-paid gallons bought there |
| Tax due or credit | Net gallons x the jurisdiction's rate |
| Net for the quarter | Sum of every jurisdiction |
We don't store IFTA rates on this site, because they change every quarter. Enter each one from the IFTA tax rate matrix for the quarter you're filing.
Source: International Fuel Tax Association · checked 2026-10
Worked example
| EXAMPLE quarter | State 1 | State 2 |
|---|---|---|
| Miles | 6,000 | 4,000 |
| Gallons bought | 500 | 1,500 |
| Fleet MPG | 5.0 | 5.0 |
| Taxable gallons | 1,200 | 800 |
| Net gallons | +700 | -700 |
| EXAMPLE rate | $0.30 | $0.40 |
| Result | $210 due | $280 credit |
Net: a $70 credit. The rates are made up for the example; real ones come from the matrix. The pattern is real, though: you owe where you drove more than you fueled, and get credit where you fueled more than you drove.
Who must file
IFTA applies to qualified motor vehicles used in more than one member jurisdiction. Under the IFTA Articles of Agreement, that's a vehicle with two axles and a gross or registered weight over 26,000 lb, a vehicle with three or more axles regardless of weight, or a combination over 26,000 lb. State agencies restate the definition; Michigan's Treasury FAQ is one clear version.
Source: Michigan Department of Treasury, IFTA FAQ · checked 2026-10
A tri-axle dump truck working inside one state, or a box truck that never crosses a state line, doesn't file IFTA. A 26 ft box truck at 26,000 lb GVWR with two axles is under the weight test, so it isn't a qualified motor vehicle unless registered heavier or towing.
Good habits that make the return easy
Record odometer miles at every state line, or let your ELD do it. Keep every fuel receipt with the gallons, the station's state and the date. Buy fuel in the jurisdictions you drive most, and reconcile monthly instead of in a panic at the end of the quarter. Missing records are what turn an IFTA audit into a bill.
Questions about this calculator
Who has to file IFTA?
Carriers running qualified motor vehicles in more than one IFTA jurisdiction. A qualified motor vehicle has two axles and a gross or registered weight over 26,000 lb, or three or more axles regardless of weight, or is a combination over 26,000 lb. A truck that never leaves its home state doesn't file IFTA, though the state may have its own fuel tax rules.
Do dump trucks need IFTA?
Only if they cross into another IFTA jurisdiction. Many dump trucks work within one state and never need IFTA. A dump truck that crosses a state line on a job is a qualified motor vehicle in most setups, because it has three or more axles or weighs over 26,000 lb.
How is IFTA calculated?
Your fleet MPG is total miles divided by total gallons for the quarter. Each jurisdiction's taxable gallons are its miles divided by that MPG. Subtract the tax-paid gallons you bought there, then multiply by that jurisdiction's rate. Positive means tax due, negative means a credit.
Where do I find current IFTA tax rates?
IFTA, Inc. publishes a tax rate matrix every quarter with each jurisdiction's rates and any surcharges. Use the matrix for the quarter you're filing; rates change, which is why this calculator asks you to enter them.
When are IFTA returns due?
Quarterly returns are due the last day of the month after the quarter ends: April 30, July 31, October 31 and January 31. File with your base jurisdiction, even if you owe nothing.
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