The federal gas tax: 18.4 cents since 1993

Every gallon of gasoline sold in the U.S. carries the same federal tax, no matter the state: 18.4 cents. Diesel pays 24.4 cents.

What it's made of

18.3 cents of excise tax plus a 0.1-cent fee that funds the cleanup of leaking underground storage tanks. For diesel, the excise is 24.3 cents plus the same fee.

Why it hasn't changed

Congress last raised the federal rate in 1993 and set it in cents, not as a percentage of the price. So when gas gets more expensive, the federal share of each gallon shrinks.

Where the money goes

Most of it goes to the Highway Trust Fund, which pays for federal highway and transit programs.

How it adds up with state taxes

States set their own rates on top. The state tables on this site show both parts together, so you can see the full tax on a gallon wherever you fill up.