The states with the highest gas tax rates

California, Washington, and Pennsylvania currently charge the highest gas taxes in the country, each above 50 cents per gallon. California leads at roughly 68 cents per gallon (as of 2024), followed by Washington at around 52 cents and Pennsylvania at approximately 58 cents. These rates change throughout the year because most states tie their gas tax to inflation or adjust it on a set schedule — so the exact amount you pay shifts even if the law stays the same.

Gas tax rates vary widely because each state sets its own rate independently. Some states use the revenue for road maintenance and bridge repairs; others direct it toward public transit or environmental programs. The federal gas tax sits at 18.4 cents per gallon and applies everywhere, but what you see at the pump is your state tax plus the federal tax combined.

Key Takeaways

  • California, Washington, and Pennsylvania have the three highest state gas tax rates, all above 50 cents per gallon as of 2024.
  • Most states adjust their gas tax rates annually based on inflation or a formula written into state law, so rates change even when lawmakers do not vote on a new bill.
  • The total tax you pay at the pump includes both your state's tax and the federal tax of 18.4 cents per gallon.
  • States with lower gas taxes include Alaska, Hawaii, and Mississippi, though Hawaii's low rate is offset by higher fuel prices overall.

How state gas taxes are structured and adjusted

Most states use one of two methods to set their gas tax: a fixed rate per gallon or an indexed rate that moves with inflation. Fixed-rate states pass a new law each time they want to change the tax. Indexed states — including California, Washington, and several others — automatically adjust the rate monthly or quarterly based on the price of fuel or a general inflation measure. This means your tax can go up or down without any new legislation.

Some states also layer on additional taxes. Washington, for example, charges a base excise tax plus a sales tax on fuel, which is why its total rate is so high. Pennsylvania uses a fixed rate but has kept it relatively high compared to neighboring states. Understanding whether your state uses a fixed or indexed system helps explain why your gas tax might jump unexpectedly in a given month.

States with the lowest gas tax rates

Alaska, Hawaii, and Mississippi have among the lowest state gas tax rates, each below 15 cents per gallon. Alaska's rate is particularly low — around 12 cents per gallon — because the state has significant oil production and historically has not relied on gas tax revenue the way other states do. Mississippi sits at roughly 18 cents per gallon, making it one of the lowest on the mainland.

However, a low gas tax does not always mean cheaper fuel overall. Hawaii has one of the lowest state tax rates but some of the highest pump prices in the nation because fuel must be shipped in and refined locally. Alaska's low tax is offset by the cost of transporting fuel to remote areas. Mississippi's low tax does translate to genuinely lower prices at the pump compared to high-tax states.

Why gas tax rates differ so much between states

States set their own rates based on their road funding needs, political priorities, and revenue goals. States with extensive highway systems and aging infrastructure — like California and Pennsylvania — tend to charge higher taxes to fund repairs and maintenance. Smaller states with less highway mileage can fund their roads with lower rates.

Some states also use gas tax revenue for purposes beyond roads. Washington directs a portion toward public transit and environmental programs. Other states reserve gas tax money strictly for highway maintenance. These different priorities shape how high each state's rate climbs. Additionally, states with lower populations sometimes have lower rates because they have fewer drivers to spread the tax burden across.

How to find your state's current gas tax rate

Your state's Department of Transportation or Department of Revenue website lists the current gas tax rate, usually updated monthly or quarterly. The Tax Foundation and the American Petroleum Institute also maintain searchable databases of state rates that update regularly. These sources show both the base rate and any additional taxes or fees your state layers on top.

When you check your state's rate, look for the effective date — rates often change on the first day of a month or quarter, and the website should show when the next adjustment takes effect. If you are comparing rates between states, remember to add the federal 18.4 cents to each state's rate to see the true total tax per gallon.

The difference between state gas tax and total fuel cost

Gas tax is only one part of what you pay at the pump. The price you see includes the cost of crude oil, refining, distribution, the retailer's margin, and then the taxes on top. Two states with similar gas tax rates can have very different pump prices depending on regional crude oil costs and refinery capacity. California's high gas tax contributes to its high prices, but the state's unique fuel blends and refinery constraints also play a major role.

When comparing states, separating gas tax from overall fuel cost helps you understand what is driving the difference. A state with a 50-cent tax might still have cheaper overall fuel than a state with a 30-cent tax if crude prices and refining costs are lower in the first state. Checking both the tax rate and the average pump price in your state gives you the full picture.

Frequently Asked Questions

Does the federal gas tax explore on top of state tax?

Yes. The federal tax of 18.4 cents per gallon applies in every state, and your state tax is added on top of that. So if your state charges 50 cents, you pay 68.4 cents per gallon in federal and state tax combined, before any local or sales taxes.

Why does my state's gas tax change month to month?

Most states use an indexed system that automatically adjusts the tax based on inflation or fuel prices. California, Washington, and many others recalculate their rate monthly or quarterly without needing a new law. States with fixed rates only change when lawmakers vote on a new bill.

Can I avoid high gas tax by buying fuel in a neighboring state?

You pay the tax of the state where you buy the fuel, not where you live. Buying in a lower-tax state saves money per gallon, but the savings are usually small — often just a few cents — and may not offset the cost of driving to a different state.

Is gas tax the same everywhere in my state?

State gas tax rates are uniform across the state, but some cities or counties add local sales tax on fuel, which varies by location. The state portion is the same whether you buy in a rural area or a city, but your total tax at the pump may differ slightly.