| Who Sets Property Taxes | Local governments — counties, municipalities, and school districts |
| Key Calculation Inputs | Assessed value × mill rate |
| Common Assessment Frequency | Annually or on a multi-year cycle, depending on the jurisdiction |
| Appeal Window | Typically 30–90 days after receiving the assessment notice |
| Most Common Exemption | Homestead exemption for primary residences |
| Where to Start | Your county assessor's office or official government website |
How Property Taxes Are Calculated
Property taxes are levied by local governments — typically counties, municipalities, and school districts — to fund public services like schools, roads, and emergency response. Your annual bill is the product of two figures: your property's assessed value and the local mill rate (also called a tax rate).
| Who Sets Property Taxes | Local governments — counties, municipalities, and school districts |
| Key Calculation Inputs | Assessed value × mill rate |
| Common Assessment Frequency | Annually or on a multi-year cycle, depending on the jurisdiction |
| Appeal Window | Typically 30–90 days after receiving the assessment notice |
| Most Common Exemption | Homestead exemption for primary residences |
| Where to Start | Your county assessor's office or official government website |
The assessed value is set by a local assessor's office and is not always the same as market value. Many jurisdictions assess at a fixed percentage of market value — commonly 80% to 100% — though this varies significantly by state and county. The mill rate is expressed in mills, where one mill equals $1 of tax per $1,000 of assessed value. Multiply your assessed value by the mill rate and you arrive at your base tax liability before any exemptions.
For example, a home assessed at $300,000 in a jurisdiction with a 20-mill rate would carry a base tax of $6,000 annually. Keep in mind that most homeowners pay into escrow accounts managed by their mortgage servicer, which collects monthly portions and pays the tax bill on their behalf. For a broader view of ongoing ownership costs, see The Real Cost of Owning a Home Beyond the Mortgage.
What Causes Your Bill to Change
Property tax bills are not static. Several factors can push them higher or lower from one year to the next:
- Reassessment cycles: Most jurisdictions reassess properties on a set schedule — annually, every few years, or when a property sells. A rising real estate market can sharply increase assessed values.
- Improvements and additions: Permitted additions, finished basements, or new structures can trigger a reassessment that raises your bill. Routine maintenance generally does not.
- Mill rate changes: Local governments adjust tax rates based on budget needs. Even if your home's assessed value stays flat, a higher mill rate raises your bill.
- Loss of exemptions: If you no longer qualify for an exemption (see below), your effective tax burden increases.
Thoughtful tracking of home improvements matters here. For guidance on managing your property as a long-term asset, including how improvements affect value and taxes, see Managing a Home as a Long-Term Asset.
Exemptions That Can Reduce What You Owe
Many homeowners pay more than necessary simply because they are unaware of available exemptions. These reduce either the assessed value or the tax owed directly. Common types include:
Assessed Value
The dollar value assigned to your property by the local assessor's office, used to calculate your tax bill. It may differ from the market value or appraised value of your home.
Mill Rate
The tax rate expressed as dollars of tax per $1,000 of assessed value. A mill rate of 15 means you pay $15 for every $1,000 of assessed value.
Homestead Exemption
A tax benefit available in most U.S. states that reduces the taxable assessed value of a primary residence, lowering the homeowner's annual property tax bill.
Assessment Notice
An official document mailed by the assessor's office notifying a homeowner of their property's newly assigned assessed value. It typically includes a deadline for filing an appeal.
Escrow Account
An account held by a mortgage servicer that collects monthly portions of the homeowner's annual property tax and insurance bills, then pays those bills on the homeowner's behalf when due.
Tax Appeal
A formal process allowing homeowners to challenge their property's assessed value if they believe it is inaccurate. A successful appeal can reduce the assessed value and lower the tax owed.
- Homestead exemption: Available in most states for a primary residence, this reduces the taxable assessed value — sometimes by a fixed dollar amount, sometimes by a percentage. Eligibility and benefit amounts vary widely. See Homestead Exemptions Across the U.S. for a detailed breakdown.
- Senior citizen exemptions: Most states offer additional reductions for homeowners above a certain age, sometimes income-tested.
- Disability and veteran exemptions: Qualifying disabled homeowners and eligible veterans may receive significant reductions or full exemptions in some jurisdictions.
- Agricultural use: Land used for farming may be assessed at a lower agricultural value rather than market value.
Exemptions typically require a one-time application through your local assessor's office. Deadlines vary — missing one can cost you a full year of savings. Check your county assessor's website for current eligibility rules.
Understanding Your Assessment Notice and Appealing It
Each year or assessment cycle, your local assessor mails an assessment notice showing the new value assigned to your property. Homeowners have a limited window — often 30 to 90 days — to file a formal appeal if they believe the valuation is inaccurate.
Common grounds for appeal include: comparable sales in your neighborhood that support a lower value, factual errors in the property record (wrong square footage, incorrect lot size, features that don't exist), and structural issues that reduce market value. Winning an appeal typically requires documented evidence, not just a feeling that the assessment seems high.
Many homeowners underestimate the process or make avoidable mistakes. For a realistic look at how appeals work and what to expect, see What Homeowners Get Wrong About Property Tax Appeals.
This article is for general informational and educational purposes only and does not constitute tax, legal, or financial advice. Property tax rules vary significantly by state and locality. Consult a qualified tax professional or your local assessor's office for guidance specific to your situation.