Washington's gas tax is a state excise tax added to every gallon of gasoline you buy
Washington State charges 49.4 cents per gallon of gasoline as of 2024. This is a state excise tax — a tax on the sale of a specific product — and it is separate from the federal gas tax of 18.4 cents per gallon that applies everywhere in the United States. When you fill up at a pump in Washington, you are paying both taxes at once, though they do not appear as separate line items on your receipt.
The state tax rate changes each quarter based on a formula tied to inflation and highway construction costs. The rate you see today may be different three months from now. Washington's gas tax is one of the highest in the nation, but the money goes directly to the state's transportation budget — roads, bridges, ferries, and public transit projects.
Key Takeaways
- Washington State charges 49.4 cents per gallon in state excise tax on top of the federal 18.4 cents per gallon.
- The state tax rate adjusts quarterly based on inflation and highway construction costs, so the exact amount changes throughout the year.
- Revenue from the gas tax funds Washington's transportation infrastructure, including state highways, bridges, ferries, and transit systems.
- The tax applies to all gasoline purchases in Washington, whether you live in the state or are just passing through.
How the quarterly rate adjustment works
Washington's gas tax is not a fixed number. The state legislature set up a formula that recalculates the tax rate every three months based on two factors: the price of crude oil and the cost of highway construction materials. When crude oil prices rise, the tax rate typically falls. When construction costs go up, the tax rate typically rises. This system was designed to keep the tax revenue stable even as fuel prices and construction expenses change.
The Department of Licensing announces the new rate on the first day of each quarter — January, April, July, and October. Gas stations update their pumps to reflect the new rate, though the change does not happen on the same day everywhere. Some stations may still be selling at the old rate for a few days while they reprogram their equipment. You can check the current rate on the Washington Department of Licensing website if you want to know the exact amount before you fill up.
What the gas tax money funds
Every cent of Washington's gas tax revenue goes into the State Transportation Fund. This money pays for maintenance and repairs on state highways, construction of new roads and bridges, ferry system operations, and grants to local governments for transit projects. The state does not use gas tax money for general government expenses like schools or social services — it is dedicated entirely to transportation.
The Washington State Department of Transportation (WSDOT) manages most of these projects. You can see where the money goes by looking at WSDOT's project lists on their website, which break down spending by region. Some of the largest ongoing projects include Interstate 5 improvements, the Tacoma Narrows Bridge toll system, and ferry terminal upgrades.
How Washington's gas tax compares to other states
Washington's combined state and federal gas tax is among the highest in the country. As of 2024, only a handful of states charge more per gallon. California charges 68.93 cents per gallon in state tax alone, while Oregon charges 36 cents per gallon. States like Wyoming and Alaska charge much less — Wyoming's state tax is 24 cents per gallon. The difference matters if you drive across state lines regularly, since you pay the tax rate of whichever state you are filling up in.
The high rate reflects Washington's commitment to funding transportation infrastructure without raising other taxes. The state has no sales tax on groceries or prescription drugs, and no income tax, so transportation funding relies heavily on the gas tax and vehicle-related fees.
Who pays the gas tax and when
Anyone who buys gasoline in Washington pays the state excise tax, regardless of where they live or how long they are staying in the state. If you live in Oregon but drive to Washington to fill up, you pay Washington's rate. If you live in Washington but drive to Oregon to fill up, you pay Oregon's rate. The tax is built into the price shown on the pump — you cannot avoid it by paying cash instead of a card, and it applies the same way to all fuel types (regular, premium, diesel).
The tax is collected by fuel distributors and wholesalers, not by individual gas stations. The station owner does not decide how much tax to charge — that comes from the state. The distributor sends the tax revenue to the state Department of Licensing, which deposits it into the State Transportation Fund.
Diesel and other fuels
Washington charges a separate excise tax on diesel fuel. As of 2024, the diesel tax is 49.4 cents per gallon — the same rate as gasoline, though it adjusts on a slightly different schedule. Propane and other alternative fuels have their own tax rates, which are generally lower than gasoline and diesel. If you drive a vehicle that runs on propane or compressed natural gas, you pay tax based on the fuel's energy equivalent rather than by the gallon.
Electric vehicles do not pay a gas tax because they do not use gasoline. However, Washington has introduced a vehicle registration fee for electric vehicles to help offset the transportation revenue lost as more drivers switch away from fuel-powered cars.
How to find the current gas tax rate
The Washington Department of Licensing publishes the current gas tax rate on their website under the Fuel Tax section. You can also call the Department of Licensing directly at 360-902-3600 to ask about the current rate. The rate changes on the first day of each quarter, so if you want to know what you will pay next month, you can check back on the first day of the next quarter to see the updated amount.
Some fuel price tracking apps and websites also display the state excise tax separately from the base fuel price, which can help you understand how much of what you pay at the pump goes to the state versus the oil company. These apps are not official government sources, but they can give you a rough idea of the breakdown.
Frequently Asked Questions
Does Washington have a gas tax holiday or temporary reduction?
Washington does not have a regular gas tax holiday. The state legislature has occasionally passed temporary suspensions or reductions during periods of very high fuel prices, but these are not automatic and require a new law each time. The most recent temporary reduction ended in 2023. The quarterly adjustment formula is the main mechanism the state uses to manage tax revenue during price fluctuations.
Why does the gas tax rate change every three months?
The quarterly adjustment keeps the tax revenue stable even when crude oil prices and construction costs change. If the tax were fixed at one rate, high oil prices would mean less tax revenue (because people buy less gas), and low oil prices would mean more revenue. The formula balances these swings so the state can plan transportation spending more reliably.
Can I deduct Washington's gas tax on my federal income tax?
No. Federal income tax rules do not allow you to deduct state gas taxes as a personal expense. If you own a business and buy fuel for business vehicles, you may be able to deduct fuel costs as a business expense, but that is different from deducting the tax itself. Talk to a tax professional about your specific situation.
What happens if I buy gas in Washington but live in another state?
You pay Washington's gas tax rate on that purchase. The tax is collected at the pump where you fill up, not based on where you live. If you regularly cross state lines for fuel, you will pay different rates depending on which state's pump you use.
Is the gas tax the same everywhere in Washington State?
Yes. The state excise tax is the same in Seattle, Spokane, and every other city in Washington. Local governments cannot add their own gas tax on top of the state rate. The only variation is the federal tax, which is the same everywhere in the country.