For 2026, the sales tax rate in King County, Washington stands at 10.25% — a combination of the 6.5% state rate and 3.75% local levy. The county's 2,270,000 residents make it an important market in the region.
For a $500 purchase in King County, the sales tax would be $51.25, bringing the total to $551.25.
Business Compliance in King County
Businesses must register with the Washington State Department of Revenue to collect and remit sales tax. Filing frequency depends on sales volume. With a population of 2,270,000, King County offers significant market potential for businesses of all sizes.