Sales tax in King County, Washington
There is no single sales tax rate in King County. It runs from 8.9% to 10.55% depending on the exact address, because cities and special districts inside the county levy their own on top of the 6.5% state rate. The 6.5% state rate applies everywhere in the county; everything above that depends on where you are standing.
What is the sales tax rate in King County?
| Washington state rate | 6.5% |
|---|---|
| Lowest combined rate in the county | 8.9% |
| Highest combined rate in the county | 10.55% |
The two combined figures are the lowest and highest totals found anywhere inside the county. They are not a state rate plus a county rate added together, and adding the rows above will not reproduce them, because cities and special districts levy in between.
Why the rate here is not the whole story
Washington charges 6.5 percent statewide and then cities, counties, transit authorities and other special purpose districts add local rates whose boundaries do not follow county lines, so a single rate for the whole county does not exist. The Department of Revenue publishes one combined local rate for each location code and does not split out the county's own share of it, so the county rate is recorded as unknown here rather than estimated. Washington counties do levy taxes of their own that apply countywide. The floor of 8.9 percent applies in the unincorporated county outside the Sound Transit district, in Carnation and Skykomish, and in the parts of Bellevue, Newcastle, and Sammamish that lie outside the Sound Transit district. The ceiling of 10.55 percent is in Seattle. The Sound Transit Regional Transit Authority adds 1.4 percent inside its own district, which covers the urban part of the county but not all of it, so the same city can appear twice in the state file with and without that tax. That district tax is neither a state nor a county levy, so do not try to rebuild these totals by adding the state and county rates.
How do I find the exact rate for an address in King County?
Because the rate changes within the county, an address is the only way to get it right. Use Washington's own lookup. A vendor's calculator is not the state speaking.
Who has to collect sales tax in King County?
A seller with a physical presence in Washington collects at the rate for the address where the sale takes place. A remote seller collects once it passes Washington's economic nexus threshold, which is a separate question from the rate and is covered on our sales tax nexus checker. Marketplace facilitators generally collect on behalf of their sellers.
How does King County compare?
See Washington sales tax for the statewide picture, including the average local rate and what is exempt. Property tax is a separate tax with separate rules: property tax in King County.
Sources
- King County rates: Washington Department of Revenue, Local Sales and Use Tax Rates by City/County, Q326_Excel_LSU-rates-alpha.xlsx, edition effective July 1 2026 through September 30 2026, https://dor.wa.gov/sites/default/files/2026-05/Q326_Excel_LSU-rates-alpha.xlsx
- Collected and verified September 9, 2026. Confidence: P on the rate components, P on the range (P read on a primary agency page, S strong but indirect, U unverified).