Car sales tax in San Mateo, California
Buying a car in San Mateo, California (San Mateo County), the combined state and local sales tax rate is 9.625%. On a $35,000 car that's about $3,376.93 in tax, and a trade-in doesn't lower it in California.
These are the figures the Before the Lot planner and its AI connector use for San Mateo, 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
San Mateo, San Mateo County: 9.625% combined state and local rate (California's rate file, rates as of 2026-10-01).
Out-the-door examples in San Mateo
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) | $85 | $85 |
| Sales tax at 9.625% | $3,376.93 | $4,820.68 |
| Title and registration (a placeholder) | $250 | $250 |
| Out the door, as dealers quote it | $38,711.93 | $55,155.68 |
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 California figure.
Doc fee and trade-in in California
- The examples use California's doc-fee cap, $85 (Veh. Code 4456.5(a)(1)); a dealer's own fee may be lower.
- A trade-in doesn't lower the taxed price in California.
- A maker's rebate doesn't lower the taxed price.
Every rule for the state, with sources: California car-buying rules.
Other places in California
- Los Angeles: 10.25%
- San Diego: 7.75%
- San Jose: 10%
- San Francisco: 8.625%
- Fresno: 8.35%
- Sacramento: 8.75%
Work out your own deal
Open the planner with San Mateo 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 San Mateo by name.
Questions
What is the car sales tax rate in San Mateo, California?
Buying a car in San Mateo, California (San Mateo County), the combined state and local sales tax rate is 9.625%. On a $35,000 car that's about $3,376.93 in tax, and a trade-in doesn't lower it in California.
What's the out-the-door price of a $50,000 car in San Mateo?
About $55,155.68: the $50,000 price, a $85 doc fee, $4,820.68 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 San Mateo?
No. California taxes the full price whatever the trade-in is worth.
Is the San Mateo rate charged on the dealer's address or mine?
California's local tax on a car goes by where the buyer lives (the address the car is registered to). California's own lookup by address: https://maps.cdtfa.ca.gov/