Federal Fuel Tax Credit Calculator
If you paid federal excise tax on fuel that you then used for a nontaxable purpose such as off-highway business use or farming, you can claim a credit on Form 4136 (Credit for Federal Tax Paid on Fuels). The credit equals the qualifying gallons multiplied by the applicable per-gallon credit rate, which generally matches the excise tax originally paid. This calculator multiplies your nontaxable gallons by the rate to estimate the credit, and shows the dollar reduction against your income tax.
Fuel tax credit formula
Credit rate ($/gal) = rate cents / 100
Estimated credit = nontaxable gallons * credit rate ($/gal)
Credit per 100 gallons = credit rate ($/gal) * 100
Annualized credit = estimated credit * 12 (if the gallons are monthly)
The credit rate is divided by 100 to convert cents per gallon to dollars. The annualized figure assumes the entered gallons represent a typical month of nontaxable use.
Fuel tax credit context
- The credit is claimed on Form 4136, Credit for Federal Tax Paid on Fuels.
- Gasoline used off-highway generally carries an 18.3-cent-per-gallon credit; undyed diesel generally 24.3 cents.
- Qualifying uses include off-highway business use, farming, and certain commercial activities.
- Personal on-highway driving does not qualify for the credit.
- The credit reduces income tax dollar-for-dollar or is refundable, unlike a deduction.
Fuel tax credit: frequently asked questions
What is the federal fuel tax credit?
The Internal Revenue Service allows a credit or refund of the federal excise tax paid on fuel used for certain nontaxable purposes, such as off-highway business use, farming, or in certain vehicles. It is claimed on Form 4136 (Credit for Federal Tax Paid on Fuels) and reduces your income tax or generates a refund.
What rate applies to my fuel?
The credit rate depends on the fuel type and use. For gasoline used off-highway the rate is generally 18.3 cents per gallon, and undyed diesel is generally 24.3 cents per gallon, matching the excise tax paid. Form 4136 lists the exact credit rate for each fuel and use type. Enter the applicable rate for your situation.
Who can claim the fuel tax credit?
Businesses and individuals who paid federal excise tax on fuel that was then used for a qualifying nontaxable purpose can claim it. Common examples include farmers, off-road equipment operators, and certain commercial uses. Personal on-highway driving does not qualify, because that is the purpose the tax funds.
How is the credit calculated?
Multiply the number of gallons used for the nontaxable purpose by the applicable credit rate per gallon. For example, 500 gallons of off-highway gasoline at 18.3 cents per gallon yields a credit of $91.50. This calculator performs that multiplication and totals multiple fuel types if you run it more than once.
Is the credit the same as a deduction?
No. A credit reduces your tax dollar-for-dollar (or is refunded), while a deduction only reduces taxable income. The fuel tax credit on Form 4136 is a credit against your income tax, so the full computed amount directly lowers what you owe or increases your refund.
Official sources
- U.S. Internal Revenue Service: About Form 4136, Credit for Federal Tax Paid on Fuels.
- U.S. Internal Revenue Service: Excise Tax.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.