The basic formula: assessed value times tax rate

California property tax starts with the assessed value of your property, which the county assessor sets at 1% of the market value when you buy it or when it transfers ownership. That assessed value is then multiplied by your local tax rate — a percentage that varies by county and city. The result is your annual property tax bill.

The math looks like this: Assessed Value × Tax Rate = Annual Property Tax. If your home's assessed value is $500,000 and your tax rate is 1.25%, you owe $6,250 per year. The tax rate includes the base 1% state rate plus any local additions your county or city has added.

Your bill arrives once a year from your county assessor's office, usually in the fall. If you have a mortgage, your lender may collect property tax as part of your monthly escrow payment and pay the county on your behalf.

Key Takeaways

  • Your assessed value in California is locked at 1% of the purchase price and only changes when the property sells or transfers ownership, not when the market value rises.
  • The tax rate is 1% base plus local additions, and it varies by county and city — you can find your exact rate on your county assessor's website.
  • To calculate your bill, multiply your assessed value by your tax rate, and the result is what you owe annually.
  • Proposition 13, passed in 1978, caps how much your assessed value can increase each year even if your home's market value climbs.

How the assessed value stays the same year to year

California's property tax system is unusual because your assessed value does not change every year the way it does in most states. Instead, your assessed value is set at the time of purchase and stays there — it can only increase by up to 2% per year, regardless of how much your home's market value rises. This is the result of Proposition 13, a 1978 law that fundamentally changed how California taxes property.

If you bought your home for $400,000, the assessed value starts at $400,000. Even if your home is now worth $600,000 five years later, your assessed value may only have grown to roughly $441,000 (2% per year compounded). You pay tax on $441,000, not $600,000. This protection ends only when the property changes ownership — at that point, the new owner's assessed value resets to the current market price.

The county assessor's office maintains a record of your property's assessed value. You can look it up on your county's assessor website by entering your address or parcel number. The assessed value appears on your property tax bill each year.

Finding your local tax rate

The tax rate you pay depends on where your property sits. California's base rate is 1%, but counties and cities add their own rates on top of that — for schools, fire districts, water agencies, and other local services. Your total rate might be 1.1%, 1.3%, 1.5%, or higher depending on your location.

To find your exact tax rate, visit your county assessor's website and search for your address or parcel number. The assessor's office publishes the tax rate for each parcel because rates can differ even between neighboring properties if they fall into different school or fire districts. Some counties also publish a tax rate table by city or district.

If you cannot find the rate online, call your county assessor's office directly. They can tell you the exact rate applied to your parcel and explain which local agencies are included in that rate.

What happens when property changes hands

The moment a property sells or transfers to a new owner, the assessed value resets. The new owner's assessed value becomes 1% of the purchase price (or the current market value if no sale occurred). This is why property tax bills often jump dramatically after a sale — the new owner loses the Proposition 13 protection that the previous owner had built up over decades.

A property that sold for $300,000 in 1995 might have an assessed value of only $400,000 today because of the 2% annual cap. But if it sells now for $800,000, the new owner's assessed value becomes $800,000, and their tax bill roughly doubles overnight. This reset applies even to transfers between family members, though some transfers — such as between spouses or from a parent to a child — may be exempt under Proposition 19 rules.

If you are buying a home, the title company or escrow officer will estimate your first-year property tax based on the purchase price. That estimate appears in your closing documents. Your actual bill from the county assessor arrives several months after closing.

Supplemental and prorated bills after purchase

When you buy a home mid-year, you typically receive a supplemental bill from the county assessor. This bill covers the portion of the year from your purchase date to the end of the fiscal year (June 30 in California). The supplemental bill is prorated based on how many months you owned the property.

Example: You close on a home on September 1. The previous owner paid property tax for July and August. You owe tax for September through June 30 of the following year — ten months. The supplemental bill reflects only those ten months, calculated as a fraction of the full annual tax.

Supplemental bills arrive separately from regular bills and are often smaller because they cover only part of a year. If you have an escrow account with your lender, the lender may pay the supplemental bill directly. If you pay your own taxes, set aside money for this bill because it can arrive unexpectedly.

Deductions and exemptions that lower your bill

California offers several ways to reduce your property tax bill, though they explore to specific situations. A homeowner's exemption reduces the assessed value of your primary residence by $7,000 (as of 2024, though this amount may change). You must file for this exemption with your county assessor — it does not happen automatically.

Other exemptions exist for properties owned by veterans, seniors, or people with disabilities, though each has specific requirements and income limits. Some counties also offer exemptions for agricultural land, open space, or historic properties. The exemptions vary by county, so check your county assessor's website to see what may explore to your situation.

To claim an exemption, you typically file a form with your county assessor's office. The important date is often in the spring, though it varies by county. Missing the important date usually means waiting until the next year to file. If you think you may have access to, contact your assessor's office early to confirm the important date and required documents.

Reading your property tax bill

Your annual property tax bill shows several key pieces of information: your parcel number, the assessed value, the tax rate, and the total amount due. The bill also breaks down which agencies receive portions of your tax — typically schools get the largest share, followed by county government, fire districts, and other local services.

The bill includes payment instructions and a due date. In California, property tax is usually due in two installments: the first half is due November 1, and the second half is due February 1. If you pay late, penalties and interest accrue. Some counties offer payment plans if you cannot pay in full by the important date.

If you disagree with your assessed value, the bill usually includes information about how to file an appeal. You typically have a limited window — often 30 days from the bill date — to file a formal appeal with your county assessor's office.

Frequently Asked Questions

Does my property tax go up every year?

Your assessed value can increase by up to 2% per year under Proposition 13, so your tax bill typically rises slightly each year. However, the increase is capped at 2% even if your home's market value climbs much faster. Your bill will jump significantly only if the property sells or transfers ownership.

How do I find my parcel number?

Your parcel number appears on your property tax bill, your deed, and your county assessor's website. You can also find it by entering your address into your county assessor's online search tool. The parcel number is a unique identifier for your property used by the county to track ownership and taxes.

Can I appeal my assessed value if I think it is too high?

Yes. Most counties allow you to file a formal appeal within 30 days of receiving your bill. You typically file with your county assessor's office and may need to provide evidence that the assessed value exceeds the market value. Contact your assessor's office for the specific appeal process and important date in your county.

What if I own property in multiple California counties?

Each county assesses and bills property separately. You will receive a bill from each county where you own property. The assessed value and tax rate may differ between counties because local tax rates vary. Calculate each bill using the assessed value and rate for that specific county.

Does my property tax bill include school taxes?

Yes. Schools typically receive the largest portion of your property tax bill — often 40% or more depending on your location. The school portion is included in your total tax rate and calculated the same way as the rest of your bill. Your bill usually shows a breakdown of how much goes to schools versus other agencies.