Washington’s gas tax is 55.4 cents per gallon on gasoline and 58.4 cents per gallon on diesel as of July 1, 2025, and it climbs automatically by 2% a year starting July 1, 2026.1Washington State Legislature. Washington Code 82.38.030 – Tax Imposed Rate Incidence Allocation of Proceeds Expiration of Subsection Add the federal excise of 18.4 cents on gasoline and 24.4 cents on diesel, and the combined per-gallon tax is 73.8 cents for gas and 82.8 cents for diesel.2U.S. Energy Information Administration. Frequently Asked Questions Every cent of the state portion is locked by the state constitution to highway and ferry use.
What You Actually Pay Per Gallon
The state rate is a stack of per-gallon levies added over the years. The base under RCW 82.38.030 is 23 cents, with successive additions built on top. On July 1, 2025, gasoline picked up a 6-cent increase, and diesel took the same increase plus an additional 3-cent surcharge. That is why, for the first time, gasoline and diesel now carry different state rates.1Washington State Legislature. Washington Code 82.38.030 – Tax Imposed Rate Incidence Allocation of Proceeds Expiration of Subsection
For the period of July 1, 2025 through June 30, 2026, the combined state and federal rates are:
- Gasoline: 55.4 cents state + 18.4 cents federal = 73.8 cents per gallon
- Diesel: 58.4 cents state + 24.4 cents federal = 82.8 cents per gallon
Because the tax is a flat per-gallon amount, it doesn’t move when the pump price rises or falls. A drop in crude prices doesn’t shrink the tax; a spike doesn’t grow it.
Scheduled Increases
The rate is on a rising schedule written into statute. Starting July 1, 2026, gasoline goes up by 2% each year, rounded to the nearest tenth of a cent. Diesel gets another 3-cent surcharge on July 1, 2027, and picks up the same 2% annual escalator starting July 1, 2028.1Washington State Legislature. Washington Code 82.38.030 – Tax Imposed Rate Incidence Allocation of Proceeds Expiration of Subsection No new bill is needed for those bumps to happen.
How the Tax Reaches the Pump
You never pay the tax directly. It’s collected at the terminal rack, the distribution point where fuel is loaded into tanker trucks. Suppliers, distributors, refiners, and blenders pay the state on each gallon they import, produce, or pull from a Washington terminal.4Washington State Department of Revenue. Motor Vehicle Fuel Tax By the time fuel gets to your station, the tax is already inside the price on the pump.
Where Your Gas Tax Money Goes
The 18th Amendment to the state constitution (Article II, Section 40) restricts fuel tax revenue to highway purposes. All motor vehicle fuel tax must go into the Motor Vehicle Fund and be spent on construction, preservation, maintenance, operation, and administration of highways and ferries.5Washington State Legislature. Striking Amendment to ESSB 5801 Resources Bill Overview The legislature can’t redirect it to schools, healthcare, or other general services.
The money is then split by formula. Counties receive roughly 16% of net state fuel taxes, distributed through grant programs run by the County Road Administration Board and the Transportation Improvement Board.6County Road Administration Board. Fuel Tax Distribution Cities also get a dedicated share. The state keeps the largest portion for statewide highway work, ferry operations, and the Washington State Patrol.
Refunds for Off-Road Fuel Use
If you burn fuel somewhere other than a public highway, you can get the state tax back. RCW 82.38.180 allows refund claims for fuel used in agricultural equipment, construction machinery on private property, power take-off equipment such as dump truck hydraulics, marine vessels, and fuel exported out of state.7Washington State Legislature. Washington Code 82.38.180 – Refund
You have 13 months from the date of purchase to file, and you need an active fuel tax refund account with the Department of Licensing before you can submit anything.8Washington State Department of Licensing. Fuel Tax Refunds Claims can be filed monthly, quarterly, or in six-month blocks. Keep the original fuel invoices showing date, seller, volume, fuel type, and tax paid. The Department does not accept estimates.
One detail catches people off guard. Unless you separately qualify for a sales tax exemption, the state deducts use (sales) tax from your refund before paying it out. For diesel claims filed in the first half of 2026, that deduction runs about 29 cents per gallon based on the average 8.7% state rate.8Washington State Department of Licensing. Fuel Tax Refunds
Dyed Diesel Penalties
Dyed diesel is untaxed fuel sold for off-road use in things like farm equipment and generators. Putting it in a licensed vehicle that drives on public roads costs $10 per gallon or $1,000 per tank, whichever is greater.9Washington State Department of Licensing. Dyed Diesel The vehicle tank and the bulk storage tank are separate violations. Fueling a truck from a 150-gallon bulk tank could mean a $1,500 fine on the storage tank plus $1,000 on the vehicle tank. Repeat violations escalate. Inspectors check for dye during roadside stops, and it’s easy to spot.
Carbon Costs Are Not the Gas Tax
Some of what you pay at the pump reflects the Climate Commitment Act, a cap-and-invest program that took effect in 2023. Fuel suppliers must buy allowances covering their annual greenhouse gas emissions through state-run auctions, and they pass that cost to consumers in the pump price.10Washington State Department of Ecology. Fuel Exemptions Under the Cap-and-Invest Program It doesn’t appear as a separate line item on your receipt.
The excise tax and the carbon cost behave differently. The excise is fixed per gallon by statute. Allowance prices move with auction demand and the shrinking emissions cap, so the carbon-related share can shift quarter to quarter. Voters had a chance to repeal the program through Initiative 2117 in November 2024 and rejected it by a wide margin. Auction revenue goes to environmental and clean energy programs and is not restricted to highway use, so it sits outside the Motor Vehicle Fund entirely.
Annual Fees for Electric and Hybrid Vehicles
Drivers who don’t buy gasoline skip the per-gallon tax, so Washington charges them through annual registration fees instead. For a fully electric car or a plug-in hybrid capable of at least 30 miles on battery power, the total is $225 a year:
- $100 base fee under RCW 46.17.323(1), split among the Motor Vehicle Fund, Transportation Improvement Account, and Rural Arterial Trust Account11Washington State Legislature. Washington Code 46.17.323 – Electric Vehicle Registration Renewal Fees Electric Motorcycles
- $50 additional fee under RCW 46.17.323(4), directed to the Motor Vehicle Fund11Washington State Legislature. Washington Code 46.17.323 – Electric Vehicle Registration Renewal Fees Electric Motorcycles
- $75 transportation electrification fee under RCW 46.17.324, deposited into the Electric Vehicle Account12Washington State Legislature. Washington Code 46.17.324 – Transportation Electrification Fee
Standard hybrids and alternative-fuel vehicles that can’t travel 30 miles on battery alone pay only the $75 electrification fee.12Washington State Legislature. Washington Code 46.17.324 – Transportation Electrification Fee Electric motorcycles pay a reduced $30 a year.11Washington State Legislature. Washington Code 46.17.323 – Electric Vehicle Registration Renewal Fees Electric Motorcycles
For comparison, a car getting 25 miles per gallon and driving 12,000 miles a year would pay roughly $266 in state gas tax at the 55.4-cent rate. The flat EV fee comes close but doesn’t scale with miles driven, so high-mileage EV drivers pay less than their gasoline counterparts and low-mileage EV drivers pay more.