Property tax starts with your home's assessed value, not its sale price

Your property tax bill is based on what your local assessor says your home is worth, not what you paid for it or what it would sell for today. The assessor's office — usually part of your county or municipality — estimates this value every few years or annually depending on where you live. That assessed value gets multiplied by your local tax rate (called the millage rate or tax rate), and the result is what you owe.

The assessed value and the tax rate are two separate numbers that both affect your bill. A home assessed at $300,000 with a tax rate of 1.2% owes $3,600 per year. The same home assessed at $250,000 with the same rate owes $3,000. Understanding which number changed — the assessment or the rate — tells you why your bill went up or down.

Key Takeaways

  • Your property tax bill equals your home's assessed value multiplied by your local tax rate, and both numbers can change independently.
  • Assessors estimate home value using sales of similar homes, income approach for rentals, or cost approach for new construction, and the method varies by location.
  • Your tax bill notice shows the assessed value, the tax rate, and the total amount due, and you can request a reassessment if you believe the value is wrong.
  • Homestead exemptions, senior exemptions, and other property tax breaks reduce your assessed value or tax rate, and you must file paperwork to claim them.
  • Property tax rates and assessment schedules differ by county and state, so your neighbor's bill does not predict yours even if your homes look identical.

How assessors determine your home's value

Assessors use three main methods to estimate property value, and which one applies to your home depends on what type of property it is. For single-family homes, the most common method is the sales comparison approach: the assessor looks at recent sales of similar homes in your area — same size, age, condition, location — and uses those prices to estimate what yours is worth. If three comparable homes sold for $320,000, $310,000, and $305,000 in the past year, your home might be assessed around $312,000.

For rental properties and apartment buildings, assessors often use the income approach. They estimate how much rent the property generates per year, subtract typical operating costs, and calculate what a buyer would pay based on that income stream. A duplex that rents for $2,000 per unit per month might be assessed differently than an identical duplex that rents for $1,500, because the income is different.

For new construction or properties with few recent sales nearby, assessors use the cost approach: they estimate what it would cost to rebuild the structure from scratch, add the land value, and subtract depreciation. This method is less common for existing homes but becomes necessary when comparable sales data is thin.

Assessors do not visit every home every year in most places. Many jurisdictions reassess on a cycle — every three years, every five years, or only when the property sells. Some states reassess annually. Check your county assessor's website to learn your local schedule, because knowing when your next reassessment is due tells you when your bill might change.

Reading your property tax bill and finding the numbers

Your tax bill is a document, usually mailed once or twice per year depending on your state, that breaks down exactly how your bill was calculated. It shows three critical pieces of information: the assessed value of your land and building separately, the tax rate (often shown as dollars per $1,000 of assessed value or as a percentage), and the total tax owed.

A typical bill might read: "Assessed value: $280,000. Tax rate: $12.50 per $1,000 of assessed value. Annual tax: $3,500." You can verify this math yourself: $280,000 ÷ $1,000 = 280. Then 280 × $12.50 = $3,500. If the math does not match, contact your assessor's office.

Your bill also lists any exemptions you receive — homestead exemption, senior exemption, veteran exemption — and shows the reduced assessed value after those exemptions are applied. If your bill shows "Assessed value before exemptions: $280,000" and "Assessed value after homestead exemption: $250,000," the exemption reduced your taxable value by $30,000, which lowers your bill proportionally.

Keep your tax bill. You will need it to prove you own the property, to challenge the assessment if you disagree with it, and to track whether your bill is rising faster than your neighbors' bills in the same area.

Why your bill changed from last year

Your property tax bill can rise or fall for two reasons: the assessed value changed, or the tax rate changed. Figuring out which one happened tells you whether to contact the assessor or your local government.

If your assessed value went up but your neighbors' did not, the assessor may have reassessed your property individually — often because you made major improvements, added a structure, or the assessor found an error in the previous assessment. If your assessed value stayed the same but your bill went up, the tax rate increased, which usually means your city or county raised the rate to fund schools, roads, or other services.

If both your assessed value and your bill went up, both factors moved against you. If your assessed value went up but your bill stayed the same or went down, the tax rate fell enough to offset the higher value. Compare your current bill to last year's bill side by side: the assessed value line and the tax rate line will show you which changed.

Exemptions and deductions that lower your bill

Most states and counties offer property tax breaks for certain owners. The most common is the homestead exemption, which reduces the assessed value of your primary residence by a fixed amount or percentage. In some states, homestead exemptions reduce the assessed value by $25,000 or $50,000. In others, they reduce the tax rate itself. The amount varies widely by state and sometimes by county within a state.

To claim a homestead exemption, you typically file a form with your assessor's office during a specific window — often in the spring or fall — and provide proof that you own and live in the home. You file once, and the exemption usually continues each year unless you move or sell. If you have never filed for homestead exemption on your current home, contact your county assessor to learn the deadline and what documents you need.

Other common exemptions include senior exemptions (age 65 or older), veteran exemptions, disability exemptions, and agricultural exemptions for working farms. Some states stack exemptions — you can claim homestead plus senior, for example — while others limit you to one. Your assessor's office can tell you which exemptions you may be may have access to to and what the paperwork requires.

Challenging an assessment you think is wrong

If you believe your assessed value is too high, you can file a formal challenge called an assessment appeal or assessment protest. The process and deadline vary by state and county, but most jurisdictions give you 30 to 60 days after you receive your bill to file. Missing the deadline usually means you cannot challenge that year's assessment.

To file an appeal, you typically submit a form to your assessor's office or county board of review and explain why you think the value is wrong. The strongest evidence is recent sales of genuinely comparable homes that sold for less than your assessed value. If three homes nearly identical to yours sold for $280,000, $275,000, and $285,000, and you were assessed at $320,000, you have a case.

You may also challenge an assessment if the assessor made a factual error — recorded your home as having four bedrooms when it has three, or listed square footage that is clearly wrong. Request your property record from the assessor's office and check it against your deed and your home's actual features. Errors in the record are often easier to overturn than disagreements about value.

Some jurisdictions hold informal hearings where you can present your case in person. Others require written submissions only. Contact your assessor's office or county board of review to learn the process in your area and what deadline applies to you.

How tax rates are set and why they vary so much

Your property tax rate is set by your local government — usually the city council, county commission, or school board — based on how much money they need to spend and how much assessed value exists in the jurisdiction. If your county needs $50 million for schools, roads, and services, and the total assessed value of all property in the county is $4 billion, the rate is roughly $12.50 per $1,000 of assessed value ($50 million ÷ $4 billion = 0.0125, or $12.50 per $1,000).

Tax rates vary dramatically between counties and states because spending needs and property values are different everywhere. A county with expensive homes and low spending needs might have a rate of $8 per $1,000. A county with less expensive homes and high spending needs might have a rate of $18 per $1,000. Two identical homes in different counties can have vastly different tax bills because of the rate difference alone.

Your tax bill notice usually shows what portion of your payment goes to schools, what portion goes to county services, and what portion goes to your city or municipality. If you disagree with how much is being spent, the remedy is to attend local government meetings and contact your elected officials — not to challenge your individual assessment.

Frequently Asked Questions

Can I lower my property tax by improving my home?

Major improvements like adding a room, finishing a basement, or replacing the roof can trigger a reassessment that raises your assessed value and your tax bill. Some states exempt certain improvements — like energy-efficient upgrades — from reassessment for a period of time. Check your state's rules before starting a project, and ask your assessor whether the work will trigger a reassessment.

What happens if I do not pay my property tax bill?

If you do not pay by the due date, you typically owe a penalty and interest. If you do not pay for several years, the county can place a lien on your home or foreclose and sell it to recover the unpaid taxes. If you cannot pay in full, contact your county treasurer or assessor about payment plans or hardship programs before the bill becomes severely overdue.

Does my property tax bill include school taxes?

Yes, in most states. Your property tax bill is usually a combined bill that includes county services, city services, and school district funding. The bill breaks down how much of your payment goes to each. Some states allow school districts to set their own tax rate separately, while others bundle everything into one rate.

How often do assessments happen, and can I request one?

Assessment schedules vary by state and county — some reassess every year, others every three to five years. You cannot request a reassessment outside the normal cycle in most places, but you can file an appeal if you think the current assessment is wrong. Contact your assessor's office to learn your local reassessment schedule and appeal deadline.

Why is my bill different from my neighbor's if our homes look the same?

Homes that look identical can have different assessed values because of differences in actual square footage, age, condition, recent renovations, or when they were last assessed. Tax rates can also differ if you live in different school districts or municipalities. Ask your assessor to explain the difference between your assessment and your neighbor's — they can show you the specific factors that affected each valuation.