How California Property Tax Is Calculated (1% + Local Levies)
Prop 13 makes California property tax simpler than most states': one statewide rate, a value that barely moves, and a few local extras.
California property tax is 1% of your assessed value (Prop 13), plus local voter-approved bond rates, plus any flat direct assessments like Mello-Roos. Average total rates run from 1.000% to 1.248% by county. Your assessed value starts at the purchase price and can rise by no more than 1% a year until you sell.
The 1% base and Prop 13
Article XIII A of the California Constitution (Prop 13, 1978) limits the general property tax to 1% of assessed value. Assessed value is set when you buy (the purchase price) or build, and is called your base year value.
Why your rate is higher than 1%
Prop 13 lets local voters approve bonds for schools, parks, water systems and other projects. Their repayment rates are added on top of the 1%. According to the State Board of Equalization's 2024-25 figures, county average total rates range from 1.000% to 1.248% (Kern). Los Angeles County averages 1.181%. Rates vary slightly within a county by tax rate area.
Separately, many bills carry direct assessments, flat charges that are not based on value: Mello-Roos community facilities districts, parcel taxes, lighting and landscaping districts. In newer developments these can add hundreds or thousands of dollars a year.
The 2% annual cap
Without a sale or new construction, your assessed value can rise by at most 1% a year, or less when California's inflation rate is lower. That's why a neighbor who bought in 1995 may pay a fraction of what you pay on an identical house. A sale resets the value to the new price. Some transfers, such as between spouses, are excluded, and parent-child transfers are limited under Prop 19.
Supplemental tax bills after you buy
The regular bill for the year you buy is usually still based on the seller's lower value. The county then sends a supplemental bill for the difference between your purchase price and the old value, prorated from the first day of the month after closing through June 30. If the presumed date falls between February 1 and June 1, you get a second supplemental bill for the full next fiscal year, because that year's regular bill was already set at the old value.
For example, a home bought in August for $800,000 that was assessed at $400,000, at a 1.181% rate, gets a supplemental bill of about $3,921 (the $400,000 difference × 1.181% × the September proration factor of 0.83). Lenders usually don't escrow supplemental bills, so budget for them.
Exemptions that lower the bill
If the home is your primary residence, file the homeowners' exemption once with the assessor. It removes $7,000 from your assessed value, worth about $70–$90 a year. Disabled veterans can exempt much more, and qualifying nonprofits can be fully exempt. See the property tax exemption finder.
A worked example
An $800,000 home in Los Angeles County with the homeowners' exemption: ($800,000 − $7,000) × 1.181% = $9,365 a year, paid in two installments, plus any direct assessments on the bill.
Estimate your bill
The California Property Tax Calculator uses every county's average rate, adds direct assessments and the homeowners' exemption, and works out your supplemental bills from your closing date.
Frequently Asked Questions
What is the property tax rate in California?
The base rate is 1% of assessed value under Prop 13. With local voter-approved bond rates added, county average total rates range from 1.000% to about 1.25%, and direct assessments such as Mello-Roos can add more.
How is assessed value determined in California?
It starts at the purchase price (or the value of new construction) and then rises by no more than 2% a year until the property is sold again or newly built on. It is usually well below market value for long-held homes.
What is a supplemental property tax bill?
An extra bill the county sends after a sale or new construction for the increase in assessed value, prorated for the rest of the fiscal year. Purchases that close from January through May usually get two supplemental bills.
When are California property taxes due?
The first installment is due November 1 and becomes late after December 10. The second is due February 1 and becomes late after April 10. Supplemental bills have their own due dates.
Can my property taxes go down in California?
Yes, if the market value falls below your assessed value. You can ask the assessor for a decline-in-value (Prop 8) review. Adding exemptions such as the homeowners' exemption also lowers the bill.
This article is for general information only. Your exact rate and charges are on your county tax bill. Contact your county assessor or tax collector for your property.