IFTA Tax Rates in Washington (2026)
Washington now runs among the highest fuel taxes in the nation: 59.5 cents a gallon on diesel and 56.5 on gasoline as of July 1, 2026, with a built-in 2 percent increase every July 1 after that. If you run I-5 or I-90, this page shows what the state collects and how to blunt it.
By the HaulMath editorial team · Updated $1
Key numbers at a glance
| Fuel | Jul 1, 2025 – Jun 30, 2026 | From Jul 1, 2026 | Source |
|---|---|---|---|
| Gasoline | 55.4¢/gal | 56.5¢/gal | Washington Department of Revenue |
| Diesel | 58.4¢/gal | 59.5¢/gal | Washington Department of Revenue |
| Combined with federal (reference) | 82.8¢ diesel | 83.9¢ diesel | Federal 24.4¢ is outside IFTA |
IFTA tax rates in Washington
Rates below are as of Q4 2026 — confirm the current official IFTA matrix before filing. Washington is jurisdiction code 53 on your IFTA return.
| Fuel | Jul 1, 2025 – Jun 30, 2026 | From Jul 1, 2026 | Source |
|---|---|---|---|
| Gasoline | 55.4¢/gal | 56.5¢/gal | Washington Department of Revenue |
| Diesel | 58.4¢/gal | 59.5¢/gal | Washington Department of Revenue |
| Combined with federal (reference) | 82.8¢ diesel | 83.9¢ diesel | Federal 24.4¢ is outside IFTA |
The mechanics behind the numbers: ESHB 2711 converted Washington's fuel tax to automatic inflation indexing, so the rate steps up about 2 percent each July 1 with no legislative vote — the 2026 step added 1.1 cents to gasoline and 1.1 cents to diesel, per the Department of Revenue and June 2026 reporting. Washington's per-gallon fuel tax now sits third-highest in the nation by recent rankings, and reporting through mid-2026 shows transportation revenue still falling short of projections despite the increase. For IFTA purposes the July 1 change lands exactly on the Q3 boundary, so your Q3 and Q4 2026 returns use 56.5/59.5 cleanly. Note that some comparison tables (the Tax Foundation's July 2026 figures show roughly 60.17/63.17 cents) add small fees on top of the base excise — the IFTA matrix line for Washington is the DOR rate shown above.
The scale is hard to overstate. At 6.5 MPG, 1,000 Washington miles burn 153.8 gallons and accrue $91.54 of diesel fuel tax — versus $36.92 in Wyoming, $30.77 in Texas and $59.23 in Utah. Per mile, that is about 9.2 cents in Washington against 3.7 cents in Wyoming. A Seattle-to-Spokane round trip alone generates roughly $75 of state fuel tax at 6.5 MPG. Model your own lanes in the IFTA calculator and stack Washington against every other state on the IFTA rates by state hub.
How Washington IFTA affects your filings
Because Washington's rate towers over its neighbors', the classic IFTA play pays off most here: buy fuel inside Washington before heading out. Every gallon pumped in the state prepays 59.5 cents of diesel tax; if your next 500 miles are in a 24-to-38 cent state, the excess comes back to you as credit on the quarterly return. The reverse — fueling cheap out of state and burning Washington miles — is the single fastest way to manufacture an IFTA bill. Compare pump price minus tax, always, and let the fuel surcharge you collect cover what the accrual says Washington is costing you (about $92 per 1,000 miles at 6.5 MPG).
The filing calendar is standard, and zero-net quarters still require a return:
| Quarter | Period | Deadline |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 30 |
| Q2 | Apr 1 – Jun 30 | July 31 |
| Q3 | Jul 1 – Sep 30 | October 31 |
| Q4 | Oct 1 – Dec 31 | January 31 (next year) |
Washington is also the state where alternative-fuel policy most affects the fuel tax base, which is why your rates keep climbing. Electric vehicle owners pay a $225 annual fee in lieu of fuel tax, and the state grants a sales and use tax exemption for qualifying clean alternative fuel vehicles and certain plug-in hybrids, per the Washington Department of Licensing. Because Washington levies no income tax, its incentives arrive as fee and sales-tax relief rather than income tax credits — a structure summarized by the DOE's Alternative Fuels Data Center. For diesel carriers the practical takeaway is simpler: as efficient vehicles shrink the taxable-gallon pool, per-gallon rates keep rising to fill the gap. Verify current figures on the DOR fuel tax rates page or the IFTA Inc. matrix each quarter.
FAQ
What is Washington's IFTA diesel tax rate in Q4 2026?
59.5 cents per gallon effective July 1, 2026, per the Washington Department of Revenue. The rate was 58.4 cents from July 1, 2025 — confirm the current figure on the official IFTA matrix before filing.
Why are Washington's fuel taxes so high?
Washington has built its transportation budget on the fuel tax for decades and is now among the top three states in the nation. Under ESHB 2711 the rate indexes upward by roughly 2 percent every July 1 automatically — the July 2026 step took gasoline from 55.4 to 56.5 cents and diesel from 58.4 to 59.5 cents.
Do Washington's rates change every year now?
Yes. The 2 percent inflation-indexed adjustment repeats each July 1 without a legislative vote, so budget on a roughly one-cent-per-gallon annual creep in your Washington IFTA lines. The change falls on the IFTA quarter boundary, so Q3 returns simply use the new rate.
What alternative-fuel credits or fees does Washington have?
Washington charges electric vehicle owners a $225 annual fee in lieu of fuel tax and offers a sales and use tax exemption for qualifying clean alternative fuel vehicles and plug-in hybrids, per the Washington Department of Licensing. Because the state has no income tax, its incentives come as fee and sales-tax relief rather than income tax credits.
How much Washington fuel tax do I pay per mile?
Taxable gallons equal Washington miles divided by your MPG. At 6.5 MPG, the 59.5-cent diesel rate works out to about 9.2 cents per mile — nearly triple Wyoming's 3.7 cents at its 24-cent rate.
Where do I verify Washington's current IFTA rates?
The Washington Department of Revenue's motor vehicle fuel tax rates page lists state, federal and combined rates with effective dates, and the IFTA Inc. quarterly matrix carries the jurisdiction line for code 53. Check both before filing.