Car sales tax in Seattle, Washington
Buying a car in Seattle, Washington (King County), the combined state and local sales tax rate is 11.05%. On a $35,000 car that's about $3,867.50 in tax; with a $10,000 trade-in, about $2,762.50.
These are the figures the Before the Lot planner and its AI connector use for Seattle, with their sources. They describe the rates and the arithmetic; they are not tax advice, and the dealer's quote and the state's documents are what count.
How the rate is made up
Seattle, King County: 11.05% combined state and local rate (Washington's rate file, rates as of 2026-10-01). Washington's local tax goes by the dealer's location, so this is the rate where the dealer is.
Out-the-door examples in Seattle
Worked with the planner's own out-the-door math for a new car, the same numbers the connector gives an AI assistant.
| Line | $35,000 car, $10,000 trade-in | $50,000 car, no trade-in |
|---|---|---|
| Vehicle price | $35,000 | $50,000 |
| Doc fee (see below) | $200 | $200 |
| Sales tax at 11.05% | $3,867.50 | $5,525 |
| Title and registration (a placeholder) | $250 | $250 |
| Out the door, as dealers quote it | $39,317.50 | $55,975 |
| Tax saved by the trade-in credit | $1,105 | — |
| Out the door after the trade-in credit | $38,212.50 | — |
The trade-in's value itself comes off what's financed or paid, not shown here. Title and registration differ by vehicle; $250 is the planner's placeholder, not a Washington figure.
Doc fee and trade-in in Washington
- The examples use Washington's doc-fee cap, $200 (RCW 46.70.180(2)); a dealer's own fee may be lower.
- A trade-in lowers the taxed price in Washington: tax is on the price less the trade-in.
- A maker's rebate doesn't lower the taxed price.
Every rule for the state, with sources: Washington car-buying rules.
Other places in Washington
Work out your own deal
Open the planner with Seattle filled in
Change the price, trade-in and fees to your own. Nothing is sent to a server; the numbers ride in the link. In Claude or ChatGPT, add the connector and ask about Seattle by name.
Questions
What is the car sales tax rate in Seattle, Washington?
Buying a car in Seattle, Washington (King County), the combined state and local sales tax rate is 11.05%. On a $35,000 car that's about $3,867.50 in tax; with a $10,000 trade-in, about $2,762.50.
What's the out-the-door price of a $50,000 car in Seattle?
About $55,975: the $50,000 price, a $200 doc fee, $5,525 in sales tax and a $250 placeholder for title and registration. A dealer's itemized quote is what counts.
Does a trade-in lower the sales tax in Seattle?
Yes. Washington taxes the price less the trade-in, so a $10,000 trade-in on a $35,000 car lowers the tax by about $1,105.
Is the Seattle rate charged on the dealer's address or mine?
Washington's local tax on a car goes by where the dealer is, not where the buyer lives. Washington's own lookup by address: https://webgis.dor.wa.gov/taxratelookup/SalesTax.aspx