Sales tax in San Mateo County, California
There is no single sales tax rate in San Mateo County. It runs from 9.375% to 9.875% depending on the exact address, because cities and special districts inside the county levy their own on top of the 7.25% state rate. The 7.25% state rate applies everywhere in the county; everything above that depends on where you are standing. These rates were read from California's own published schedule and checked on October 1, 2026. The rate in each of the 20 cities is in the table below.
What is the sales tax rate in San Mateo County?
| California state rate | 7.25% |
|---|---|
| San Mateo County rate | 2.125% |
| Lowest combined rate in the county | 9.375% |
| Highest combined rate in the county | 9.875% |
The combined figures are the lowest and highest totals anywhere in San Mateo County, so the rows above do not add up to them.
What is the sales tax rate in each city in San Mateo County?
California publishes the rate for every city it taxes. These are the combined rates, state and local together, as listed in California's own rate file.
| City | October 1, 2026 onward |
|---|---|
| Atherton | 9.375% |
| Belmont | 9.875% |
| Brisbane | 9.875% |
| Burlingame | 9.625% |
| Colma | 9.875% |
| Daly City | 9.875% |
| East Palo Alto | 9.875% |
| Foster City | 9.375% |
| Half Moon Bay | 9.875% |
| Hillsborough | 9.375% |
| Menlo Park | 9.375% |
| Millbrae | 9.375% |
| Pacifica | 9.875% |
| Portola Valley | 9.375% |
| Redwood City | 9.875% |
| San Bruno | 9.875% |
| San Carlos | 9.375% |
| San Mateo | 9.625% |
| South San Francisco | 9.875% |
| Woodside | 9.375% |
| Unincorporated San Mateo County | 9.375% |
Source: California rate file for October 1, 2026 onward, from California's official rate page.
How much sales tax is that on a purchase in San Mateo County?
At 9.375%, a $100 purchase carries $9.38 in sales tax and a $1,000 purchase $93.75, at the lowest rate in the county. At the highest, 9.875%, the same purchases carry $9.88 and $98.75. That is general merchandise; California taxes some categories, often groceries, differently, as the note below explains.
Among California's 58 counties, San Mateo County's lowest rate ranks 4th highest. See every California county.
Sales tax in counties next to San Mateo County
San Mateo County borders 4 counties. The lowest rate next door is 8.625% in San Francisco County, CA, which is $7.50 less on a $1,000 purchase than the lowest rate in San Mateo County.
| County | Combined sales tax |
|---|---|
| Alameda County, CA | 10.25% to 10.75% |
| Santa Clara County, CA | 9.75% to 10.5% |
| San Mateo County, CA (this county) | 9.375% to 9.875% |
| Santa Cruz County, CA | 9.25% to 9.75% |
| San Francisco County, CA | 8.625% |
Why the rate here is not the whole story
California levies 7.25% statewide and San Mateo County adds a countywide district tax of 2.125%, bringing the countywide rate to 9.375%. Cities and special districts inside the county add more on top, so the combined rate runs from 9.375% to 9.875% depending on the address. District taxes are approved by voters in individual cities and districts and do not follow county lines, so use the CDTFA address lookup for a specific location.
How do I find the exact rate for an address in San Mateo County?
Use California's own address lookup. In San Mateo County the rate depends on the address, anywhere from 9.375% to 9.875%.
Who has to collect sales tax in San Mateo County?
Any seller with a physical presence in California collects at the rate for the address of the sale; a remote seller does once it passes California's economic nexus threshold. California sales tax covers the statewide rules and what is exempt.
Work out your own numbers
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Sales tax calculator
Tax on a specific purchase at this county's rate, and the total you will actually pay.
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Do you have to collect?
Whether your sales into California cross its economic nexus threshold. A different question from the rate.
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Property tax in San Mateo County
The other local tax: effective rate and median bill for this county.
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Sales tax by county
Every US county, and how California compares with the rest of the country.
Sources
- San Mateo County rates: California Department of Tax and Fee Administration, CDTFA-95 California Sales and Use Tax Rates by County and City, REV. 39 (10-26), operative October 1, 2026, cross-checked against CDTFA's downloadable rate file Tax Rates Effective October 1, 2026 (SalesTaxRates10-1-26.xlsx)
- Collected and verified October 1, 2026. Confidence: P on the rate components, P on the range (P read on a primary agency page, S strong but indirect, U unverified).