Washington's gas tax rate and what it covers

Washington State charges 49.4 cents per gallon of gasoline as of 2024. This is one of the highest gas taxes in the country. The tax funds road maintenance, bridge repairs, and public transportation projects across the state.

The 49.4 cents breaks down as follows: 18.4 cents is the federal excise tax (the same in every state), and 31 cents is Washington's state tax. When you fill up, both are included in the price you see on the pump — they are not added separately at checkout.

Washington's state portion has increased over time. The state legislature passed a fuel tax increase in 2015 that raised the rate from 37.5 cents to 49.4 cents per gallon, phased in over several years. The revenue goes into the Transportation Improvement Account, which pays for specific projects named in state law.

Key Takeaways

  • Washington State's gas tax is 31 cents per gallon on top of the 18.4-cent federal tax, totaling 49.4 cents per gallon.
  • The state tax funds road repairs, bridge maintenance, and public transportation through the Transportation Improvement Account.
  • Washington's gas tax is among the highest in the nation and has not changed since the 2015 increase took full effect.
  • The tax is included in the pump price you see — it is not a separate charge at the register.

How Washington's gas tax compares to other states

Washington ranks in the top five states for gas tax rates. California charges 68.4 cents per gallon, Illinois charges 50.4 cents, and Indiana charges 50.7 cents. States like Wyoming (41.4 cents) and Nevada (47.6 cents) charge less. The national average state gas tax is around 30 cents per gallon, so Washington is above that mark.

The difference matters over time. A driver who fills a 15-gallon tank weekly in Washington pays about $229 per year in state gas tax alone. In a lower-tax state like Wyoming, the same driver would pay about $102 per year in state tax — a difference of roughly $127 annually.

What the gas tax money actually funds

Washington's 31-cent state gas tax goes into the Transportation Improvement Account. The legislature allocates this money to specific projects: highway expansion, bridge repairs, ferry system improvements, and public transit grants to cities and counties. The Washington State Department of Transportation (WSDOT) manages most of the highway and bridge work.

The state also dedicates a portion to the Multimodal Transportation Account, which supports transit agencies like King County Metro and Pierce Transit. Local governments can receive grants for road repairs and safety projects. The exact breakdown changes year to year based on the state budget, but roughly 70 percent goes to highway and bridge work, with the remainder split among transit and local projects.

Why Washington's gas tax is high

Washington has no state income tax, so the state relies more heavily on sales tax, property tax, and fuel tax to fund services. The gas tax is one of the largest dedicated revenue sources for transportation. The 2015 increase was passed to address a backlog of road repairs and fund new projects, particularly in the Seattle and Tacoma regions where traffic congestion was growing.

The state legislature has not raised the gas tax since 2015. However, the rate is adjusted annually for inflation under a formula set in state law. This means the effective tax rate creeps up slightly each year without a new vote — in 2024, the inflation adjustment added about 1 cent to the rate compared to 2023.

Diesel tax and other fuel taxes in Washington

Washington charges a separate tax on diesel fuel: 49.4 cents per gallon, the same as gasoline. This includes the 24.4-cent federal diesel tax and Washington's 25-cent state diesel tax. Diesel drivers pay slightly less in state tax than gasoline drivers (25 cents versus 31 cents), but the federal portion is higher, so the total is the same.

Alternative fuels like compressed natural gas (CNG) and propane are taxed differently. CNG is taxed at 27.3 cents per gallon equivalent, and propane at 27.3 cents per gallon equivalent. Electric vehicles pay no fuel tax, though Washington has discussed other ways to fund road maintenance as more drivers switch to electric.

How to estimate your annual gas tax bill

To calculate what you pay in Washington gas tax per year, multiply your annual gallons purchased by 0.31 (the state portion). The average American driver uses about 600 gallons per year, which means roughly $186 per year in Washington state gas tax alone.

If you drive a fuel-efficient car that gets 30 miles per gallon and you drive 12,000 miles per year, you will buy 400 gallons annually. At 31 cents per gallon, that is $124 per year in state tax. A less efficient vehicle getting 20 miles per gallon would cost about $186 per year. Adding the federal 18.4 cents brings the total to about $310 per year for the efficient car and $465 for the less efficient one.

Frequently Asked Questions

Does Washington's gas tax explore to diesel and other fuels?

Yes. Diesel is taxed at 49.4 cents per gallon total (25 cents state, 24.4 cents federal). Compressed natural gas and propane are taxed at 27.3 cents per gallon equivalent. Electric vehicles are not subject to fuel tax, though the state is studying alternative funding methods as EV adoption grows.

When was the last time Washington raised the gas tax?

The most recent increase was in 2015, when the rate rose to 49.4 cents per gallon. Since then, the rate adjusts annually for inflation under state law, but no new legislative increase has occurred. The inflation adjustment typically adds a fraction of a cent each year.

Where does my gas tax money go?

Most goes to highway and bridge repairs through the Washington State Department of Transportation. The remainder funds public transit grants to cities and counties, ferry system improvements, and local road projects. The exact allocation changes with the state budget each year.

Is Washington's gas tax the highest in the country?

No. California (68.4 cents), Illinois (50.4 cents), and Indiana (50.7 cents) all charge more. Washington ranks around fifth nationally. However, it is well above the national average state gas tax of about 30 cents per gallon.

Do I pay gas tax on every gallon I buy in Washington?

Yes, every gallon of gasoline or diesel purchased in Washington is subject to the state tax, regardless of where you live or where you plan to drive. The tax is built into the pump price you see.