How is this calculated?
Taxable gallons per jurisdiction = jurisdiction miles / fleet MPG Tax owed per jurisdiction = taxable gallons * tax rate - purchased gallons * tax rate Net IFTA = sum of jurisdiction tax owed Positive net = tax due; negative net = credit
Example: 800 miles in Texas at 6.5 MPG creates 123.08 taxable gallons. At $0.20 per gallon, tax is $24.62 before subtracting tax-paid Texas fuel purchases.
How do I use this calculator?
- Choose the unit or currency setting that matches your vehicle data.
- Enter the required vehicle, route, fuel, weight or loan values in the calculator form.
- Review inline warnings and correct any missing or negative inputs.
- Read the live result card for the primary answer and supporting totals.
- Use the worked example if you want to check the formula with sample values.
- Copy, share or print the results for comparison or record keeping.
What do the terms mean?
- IFTA
- International Fuel Tax Agreement for interstate motor fuel tax reporting.
- Jurisdiction
- An IFTA member state or province.
- Fleet MPG
- Total qualified miles divided by total gallons for the reporting period.
- Taxable gallons
- Jurisdiction miles divided by fleet MPG.
- Credit
- A negative net amount when fuel tax paid exceeds fuel tax owed.
What are real-world examples?
| Scenario | Inputs | Result | Notes |
|---|---|---|---|
| Texas lane | 800 mi, 6.5 MPG | $24.62 gross | $0.20 diesel rate |
| California lane | 500 mi, 6.5 MPG | $74.69 gross | $0.971 diesel rate |
| Ontario lane | 600 mi, 6.5 MPG | $22.98 gross | $0.249 diesel rate |
| Oregon miles | Report miles | $0 fuel rate here | Weight-mile tax separate |
What tips improve accuracy?
- Always verify current IFTA rates at IFTA Inc. before filing an official return.
- Use total fleet MPG for the quarter, not state-by-state MPG.
- Keep fuel receipts with jurisdiction, gallons and tax-paid status.
- Oregon has a zero IFTA fuel tax rate in the matrix but separate weight-mile rules.
- Some jurisdictions have surcharge lines that may not create credits.
- IFTA returns are generally due by the last day of the month after quarter end.
Did you know? EPA estimates commonly use 8.89 kg CO2 per gallon of gasoline and 10.18 kg CO2 per gallon of diesel for tailpipe carbon dioxide calculations.
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Frequently asked questions
Are the 2026 IFTA rates final?
The current-quarter IFTA matrix can change before it is finalized. This page labels the rates as planning estimates and links to IFTA Inc. so carriers can verify before filing.
What MPG should I use for IFTA?
Use the fleet average MPG for the reporting quarter: total qualified miles divided by total gallons consumed.
Is this calculator free to use?
Yes. The calculator runs in your browser, does not require an account and can be printed or copied for your records.
Can I use this for official tax, loan or compliance filing?
Use it as an estimate. For official filing, financing or enforcement decisions, verify the final numbers with your lender, tax authority, manufacturer rating label or compliance professional.
Why are my real-world results different?
Real vehicles vary with load, speed, terrain, temperature, tire condition, maintenance, driver behavior and measurement quality.
Does the calculator save my units?
Yes. Unit and currency selections that are marked as preferences are stored in localStorage on your device so the next visit starts with your preferred setting.
Can I share the result?
Yes. Use the Share button if your browser supports native sharing, or copy the permalink and result summary.
Does it work on mobile?
Yes. The layout stacks on small screens, keeps labels visible and recalculates as you type.
How accurate are the formulas?
The formulas are standard industry math for estimates. Accuracy depends on the input values and whether the assumptions match your vehicle and jurisdiction.
When was this page updated?
This page was last updated on 2026-05-01 for 2026 planning assumptions and source links.