How sales tax works in King County (Seattle)
Purchases in King County (Seattle) carry a combined sales tax of about 10.35% — the Washington state rate plus county and city add-ons.
Sales tax is added at checkout to the price of taxable goods, so the total is the listed price plus the combined rate.
The exact rate can vary slightly between cities within King County (Seattle); this uses a typical combined figure for the area.
Why the rate varies within Washington
Counties and cities set their own local sales tax on top of the state rate, so two locations in Washington can charge different totals.
For the precise rate at a specific address, check by ZIP code with the King County Assessor (kingcounty.gov) or the state revenue department.
What is taxed
Most physical goods are taxable, while many areas exempt or reduce tax on groceries and prescriptions.
This is a planning estimate at the typical combined rate. Confirm the rate and exemptions for your purchase with the King County Assessor (kingcounty.gov).
Frequently asked questions
What is the sales tax rate in King County (Seattle)?
The typical combined sales tax rate in King County (Seattle) is about 10.35%, including the Washington state rate plus local add-ons.
How do I calculate King County (Seattle) sales tax?
Multiply the purchase amount by 10.35%. This calculator does it and shows the tax and total instantly.
Is the rate the same across King County (Seattle)?
Not always — cities within the county can add their own tax, so the rate varies slightly by address. This uses a typical combined figure.
Are groceries taxed in King County (Seattle)?
Many areas exempt or reduce tax on groceries and prescriptions. Check the King County Assessor (kingcounty.gov) for the categories that apply.