California Property Tax Calculator
Calculate your annual California property tax by county, see exactly how Prop 13 reduces your tax bill compared to market value, and compare effective rates across 8 major counties.
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How to Use This Calculator
Annual Tax tab
Enter your home value and select your county. The calculator applies the county's effective property tax rate — which includes the Prop 13 base rate of 1% plus voter-approved bonds, Mello-Roos, and local assessments — to estimate your annual and monthly property tax. Results also show how your home compares to the county median.
Prop 13 Impact tab
This is the tab unique to California. Enter your purchase year, purchase price, and current market value. The calculator computes your Prop 13 assessed value (purchase price growing at 2% per year), compares it to market value, and shows exactly how much Prop 13 saves you annually. Long-term owners often save thousands per year compared to what a new buyer would pay.
County Comparison tab
See all 8 major California counties side by side: effective tax rate, median home value, and median annual property tax. Sorted by median tax from lowest to highest. Useful for comparing total housing costs across California metro areas.
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Why California Property Tax Is Different
California's Prop 13 means your property tax is based on purchase price, not current market value. A home bought in 2000 for $300K is assessed at roughly $450K today even if it's worth $1.2M. New buyers pay 2-3 times more in property tax than long-term neighbors in identical homes.
This creates a “lock-in effect” — selling means losing your low tax base. A homeowner paying $4,500/year on a $1.2M home would owe $12,000+ per year if they sold and rebought at the same price. Prop 19 (2021) partially addresses this for homeowners 55 and older, allowing them to transfer their tax base to a new home anywhere in California up to 3 times.
The Formula
California property tax is calculated on assessed value, not market value:
Where:
Assessed Value = Purchase Price × (1.02)^(years since purchase)
Base Tax Rate = 1% of assessed value (Prop 13)
Effective Rate = Base 1% + voter-approved bonds + Mello-Roos + local assessments
Typical effective rates by county:
Los Angeles: 0.72% | San Diego: 0.73% | Orange: 0.70%
San Francisco: 1.18% | Santa Clara: 0.75% | Alameda: 0.88%
Sacramento: 0.83% | Riverside: 1.05%
Assessment resets to market value upon: sale, new construction, or change of ownership
The 2% annual cap on assessment increases is the core of Prop 13. In areas where home values have appreciated 5-10% annually, the gap between assessed value and market value grows dramatically over time. After 20 years of 7% appreciation, market value can be 3-4 times the assessed value.
Example
Maria — Long-term homeowner in Los Angeles
Maria bought a home in Pasadena in 2005 for $400,000. In 2026, similar homes on her street sell for $900,000. Here is how Prop 13 affects her property tax:
Prop 13 assessed value
Tax comparison
Maria pays $4,226/year while her new neighbor who bought the identical house next door for $900,000 pays $6,480/year. If Maria had bought in 1990, the gap would be even larger — her assessed value would be roughly $300,000 on a $900,000 home, saving her nearly $4,300/year.