What is Iowa's gas tax rate?

Iowa's gasoline excise tax is 30 cents per gallon for regular gasoline. Ethanol blends such as E15 receive a slightly lower rate of about 27 cents per gallon, and diesel is taxed at 32.5 cents per gallon. These rates are set by the Iowa legislature.

Does Iowa tax E15 and ethanol blends differently?

Yes. Iowa applies a reduced excise rate to higher ethanol blends like E15 to encourage their use, currently around 27 cents per gallon versus 30 cents for regular gasoline. Diesel and biodiesel blends carry their own rates.

How much federal gas tax do I pay?

The federal gasoline excise tax is 18.4 cents per gallon and the federal diesel excise is 24.4 cents per gallon. These rates have been unchanged since 1993 and are added on top of Iowa's state excise at the pump.

Is gas tax included in the pump price?

Yes. Both the Iowa state excise and the federal excise are baked into the per-gallon price you see at the pump, so you do not pay them separately. This calculator simply breaks out how much of your spending is tax.

How is tax per mile calculated?

Tax per mile is the combined per-gallon excise divided by your fuel economy in miles per gallon. A more efficient vehicle spreads the same per-gallon tax over more miles, so it pays less fuel tax for each mile driven.

Iowa Gas Tax Calculator

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Every gallon you pump in Iowa includes a state excise tax and a federal excise tax built into the price. This calculator shows how much fuel tax you pay over a year and breaks it down to the cost per mile driven.

How it works

You can estimate your gallons two ways, then the tool applies both excise rates:

gallons = annual miles ÷ mpg   (or)   tank size × fill-ups per year
state tax = gallons × Iowa excise
federal tax = gallons × federal excise
tax per mile = (Iowa excise + federal excise) ÷ mpg

Iowa’s excise is 30 cents per gallon for regular gasoline, about 27 cents for E15, and 32.5 cents for diesel. Federal excise adds 18.4 cents for gasoline and 24.4 cents for diesel.

Example

Driving 12,000 miles a year at 25 mpg burns about 480 gallons. At 30 cents Iowa excise that is $144 in state tax, plus $88 federal at 18.4 cents, for about $232 of fuel tax a year, or roughly 1.9 cents per mile.

Notes

These excise rates are included in the pump price, not added separately. Iowa periodically adjusts its ethanol-differential rates, so confirm current figures at tax.iowa.gov. The tool covers excise only and not retail sales tax, which Iowa does not apply to motor fuel.