Every time you fill up, the price on the sign is a stack of numbers: the wholesale price of crude, the refinery margin, the distributor markup, and — sitting quietly at the bottom — the taxes. Two taxes in particular follow you everywhere you drive in the United States: the federal excise tax on gasoline, which is a flat 18.4 cents per gallon no matter which state you are in, and your state's own gasoline excise tax, which ranges from about 9 cents a gallon in Alaska to more than 70 cents a gallon in California.
This gas tax by state calculator adds those two numbers together, multiplies by how much fuel you actually burn in a year, and shows you the annual tax bill hidden inside your fill-ups. It also lets you compare what you pay in your home state against the federal-only baseline, so you can see exactly how much extra your state is charging you at the pump.
How to Use
- Enter your Annual Gasoline Purchased. If you do not know this exactly, divide your annual miles driven by your car's MPG — a typical American driver puts 13,500 miles on the road each year in a car that averages 27 MPG, which works out to about 500 gallons.
- Set the State Gas Tax Rate for the state you live in. The default of 51.1 cents per gallon reflects California's combined excise rate; look up your state on the Tax Foundation's "Gas Taxes by State" table if you live elsewhere.
- Leave the Federal Gas Tax Rate at 18.4 cents unless you have a specific reason to change it — that rate has not moved since 1993 and is identical in all 50 states.
- Add a Local / Option Tax if your county or municipality levies its own fuel tax. Most drivers can leave this at zero; a handful of states (such as New York's Metropolitan Commuter Transportation District) layer on a few extra cents.
- Read the result card. The headline number is your Annual Total Gas Tax — the combined federal + state + local tax you will pay this year just by fueling your car.
The card also breaks the tax into federal, state, and local pieces, shows the total tax per gallon, and reports how much extra your state and local layers add on top of the federal-only baseline.
How Gas Tax Is Built
Every gallon of gasoline sold in the United States carries two layers of excise tax:
- Federal tax — 18.4 cents per gallon. This feeds the Highway Trust Fund and is set by Congress. It was last raised in 1993 and has not been adjusted for inflation since, which means its real purchasing power has been cut roughly in half over the last thirty years.
- State tax — roughly 9 to 70 cents per gallon. Each state sets its own rate, usually on a cents-per-gallon basis rather than as a percentage of pump price. As of the most recent Tax Foundation survey, California levies the highest state gas tax at about 73.6 cents per gallon, followed by Illinois and Pennsylvania; Alaska has the lowest at about 9 cents per gallon.
- Local-option taxes — 0 to several cents per gallon. A small number of counties, cities, and transit authorities layer their own fuel taxes on top of the state rate.
The math is deliberately simple:
Annual tax (USD) = annual gallons × (federal cents + state cents + local cents) ÷ 100
Worked example at the defaults: 500 gallons × (18.4 + 51.1 + 0) cents = 500 × 69.5 cents = 34,750 cents = $347.50 per year. Of that, $92.00 goes to the federal Highway Trust Fund and $255.50 goes to your state.
Why State Gas Taxes Vary So Much
Two drivers buying the same 12-gallon fill-up at the same pump price can pay very different tax bills depending on where they live. A driver in Alaska pays 18.4 + 9.0 = 27.4 cents per gallon in tax; a driver in California pays 18.4 + 51.1 (or more, after recent adjustments) = nearly 70 cents per gallon. On a 500-gallon year, that gap is roughly $200 of tax difference — money that in California funds road maintenance, transit, and climate programs, while in Alaska the low gas tax is paired with no state income tax at all.
States also differ in how they adjust the rate. Some, like California and Pennsylvania, index their gas tax to fuel prices or inflation, so the cents-per-gallon number rises automatically each year. Others set a fixed number that legislature must vote to change, which is why a few states have nominally low rates that have eroded in real terms.
Examples
Example 1 — The default California commute. A driver burns 500 gallons a year in a state with a 51.1-cent excise tax. The federal tax is 18.4 cents, so the total tax per gallon is 69.5 cents. Annual federal tax is $92.00, annual state tax is $255.50, and the combined annual gas tax bill is $347.50 — about $29 per month.
Example 2 — Low-tax Alaska. The same 500 gallons in Alaska, where the state tax is 9.0 cents, gives a total tax of 27.4 cents per gallon and an annual bill of only $137.00. Even though the federal portion is still $92.00, the state layer is small enough that the whole tax burden feels noticeably lighter at the pump.
Example 3 — High-mileage driver. A road-warrior salesperson burns 3,000 gallons a year in California. The total tax per gallon stays at 69.5 cents, but the annual bill jumps to 3,000 × $0.695 = $2,085.00 — and the state's share alone is $1,533. That is the kind of number that makes switching to a hybrid or an EV look much more attractive, because the fuel-tax savings scale directly with mileage.
Example 4 — Fleet operator. A small delivery business buys 10,000,000 gallons a year. At 69.5 cents per gallon the annual tax bill is $6,950,000, of which $5,110,000 is state tax. On numbers that large, even a 0.5-cent change in the state rate is a $50,000 swing — which is why fleet owners lobby statehouses directly on fuel-tax legislation.
FAQ
How much is the federal gas tax per gallon?
The federal excise tax on gasoline is a flat 18.4 cents per gallon in every U.S. state and the District of Columbia. It is deposited into the Highway Trust Fund and was last increased in 1993. Diesel carries a higher federal rate of 24.4 cents per gallon.
Which state has the highest gas tax?
As of the latest Tax Foundation survey, California has the highest state gasoline tax, at roughly 73.6 cents per gallon when all excise and fee layers are counted. Illinois and Pennsylvania follow. The exact number changes every year because California indexes its rate to fuel prices and inflation.
Which state has the lowest gas tax?
Alaska has the lowest state gas tax at about 9.0 cents per gallon. New Jersey has the next-lowest excise rate, in the low teens. Alaska pairs its low gas tax with no broad state income tax, so the burden is shifted away from drivers.
Is the gas tax different for diesel?
Yes. The federal diesel tax is 24.4 cents per gallon (versus 18.4 cents for gasoline), and most states also set a separate, higher rate for diesel. This calculator is built for gasoline; if you drive a diesel pickup or truck, add roughly 6 cents per gallon to the federal line and look up your state's separate diesel rate.
Do local or county fuel taxes count?
A small number of areas — most notably New York City's metropolitan commuter zone, a few Colorado counties, and parts of Illinois — add a few extra cents per gallon on top of the state rate. Use the Local / Option Tax field to fold that in; for most drivers it is zero.
Is gas tax a percentage or a fixed amount per gallon?
It is almost always a fixed cents-per-gallon excise tax, not a percentage of pump price. That means when the price of crude rises sharply, the tax as a share of the pump price actually falls, and when gasoline is cheap the tax share rises. A handful of states (including California) tie their cents rate to inflation or fuel prices, which re-introduces a partial price index.
How does my state gas tax compare to the federal baseline?
Enter your annual gallons and state rate, then read the State Tax Above Federal-Only line. That number is the extra dollars your state and local layers collect on top of the $18.4-cent federal baseline. In California on 500 gallons it is about $255; in Alaska it is only about $45.
Disclaimer
This gas tax by state calculator is provided for informational purposes only and does not constitute tax, legal, or financial advice. State and federal fuel-tax rates change frequently, are indexed to inflation in some states, and may not reflect special exemptions, commercial-use discounts, or local-option levies in your exact county. Always verify the current rate with your state department of revenue or the Tax Foundation's latest "Gas Taxes by State" table before making a financial decision.