Property tax starts with an assessed value, not the price you paid

Your property tax bill is built on a number that your local assessor decides: the assessed value of your home or land. This is not the same as what you paid for it, what you could sell it for, or what your mortgage lender says it is worth. The assessor estimates what your property would sell for on the open market, then the local government applies a tax rate (also called a millage rate) to that value. The result is your annual property tax bill.

The assessed value is the foundation of the entire calculation. If the assessor values your home at $300,000 and your local tax rate is 1.2%, your bill would be $3,600 before any exemptions or credits. But if the assessor values it at $250,000 with the same rate, your bill drops to $3,000. That is why understanding how assessors arrive at their number matters — and why property owners often challenge assessments.

Key Takeaways

  • Assessed value is set by your local assessor and is based on what your property would sell for, not what you paid or what a lender thinks it is worth.
  • The tax rate (millage rate) is set by your local government and varies by county, city, school district, and other local services you receive.
  • Your bill is calculated by multiplying assessed value by the tax rate, then subtracting any exemptions or credits you are may have access to to.
  • Assessments happen on different schedules in different places — some counties reassess every year, others every three to five years.
  • If you believe your assessment is too high, you can file a formal challenge called an appeal or grievance, usually within a set window after you receive your notice.

How assessors determine the value of your property

Assessors use three main approaches, and which one they use depends on what kind of property you own. For a single-family home, the most common method is the sales comparison approach: the assessor looks at recent sales of similar homes in your area and adjusts for differences. If your home sold for $320,000 two years ago and similar homes have sold for $310,000 to $330,000 recently, your assessed value might land somewhere in that range.

For rental properties or commercial buildings, assessors often use the income approach, which estimates value based on how much income the property generates. A four-unit apartment building that rents for $1,500 per unit per month is valued differently than an identical building that rents for $1,200 per unit, because the income is different.

The third method, the cost approach, is less common but used for newer construction or unusual properties. It adds the land value to the cost of rebuilding the structure, minus depreciation. An assessor might say: the land is worth $100,000, the building would cost $250,000 to rebuild new, but it is 20 years old so subtract 30% for wear, giving a total value of $275,000.

Most assessors blend these methods or use the one that makes the most sense for your property type. They also use public records (deed transfers, mortgage amounts), property characteristics (square footage, lot size, age, condition), and sometimes physical inspections to refine their estimate.

Understanding the tax rate and how it is set

The tax rate is expressed as a percentage or as mills per dollar of assessed value. One mill equals one-tenth of one percent, so a rate of 12 mills means 1.2% of assessed value. Your property tax bill goes to multiple entities — your county, your city or township, your school district, and sometimes special districts for fire, water, or library services. Each one sets its own rate.

If you live in a county where the county rate is 4 mills, the city rate is 5 mills, the school district rate is 18 mills, and the fire district rate is 2 mills, your total rate is 29 mills (2.9%). That rate is applied to your assessed value. Rates vary widely by location — some counties are under 1%, others exceed 2.5% — because they depend on local spending needs and the total assessed value in the area.

Tax rates are set by elected bodies: county commissioners, city councils, school boards, and special district boards. They are usually set once a year, often in late summer or fall, and they are public information. You can find your local rates on your county assessor's website or your property tax bill itself, which breaks down how much you owe to each entity.

The role of exemptions and credits in lowering your bill

After the assessor sets a value and the tax rate is applied, your bill may be reduced by exemptions or credits. These are not the same thing. An exemption removes a portion of your assessed value from taxation entirely. A homestead exemption, available in many states, might exempt the first $50,000 of your home's value from taxation. If your home is assessed at $300,000 and you have a $50,000 homestead exemption, you pay tax on only $250,000.

A credit is a dollar-for-dollar reduction in the tax you owe after it is calculated. If your bill is $3,600 and you have a $500 property tax credit, you pay $3,100. Credits are often tied to income, age, disability, or military service. Some states offer credits for solar installations or energy-efficient improvements.

Common exemptions include homestead exemptions (for primary residences), agricultural exemptions (for farmland), and exemptions for religious or charitable organizations. may be able to access and amounts vary by state and sometimes by county. You typically have to file a form with your assessor to claim an exemption; it does not happen automatically. Credits are sometimes claimed on your state income tax return instead.

When assessments happen and how often they change

Assessment schedules vary by location. Some counties reassess every year, updating values to reflect current market conditions. Others reassess every three, four, or five years. A few states use a hybrid system where some properties are reassessed annually and others on a longer cycle.

When a reassessment happens, your assessed value may go up, down, or stay the same depending on market conditions and property changes. If you made major improvements — an addition, a new roof, a pool — the assessor may increase your value. If your neighborhood has declined or you have deferred maintenance, it may decrease. If nothing has changed and the market is stable, it may stay the same.

You will receive a notice when your assessment changes, usually 30 to 60 days before your tax bill is due. The notice tells you the new assessed value and often explains what changed. This is your window to file an appeal if you disagree with the new value.

How to read your property tax bill and find the numbers

Your property tax bill is a document that breaks down the calculation step by step. At the top, you will see your property address and parcel number (a unique identifier for your land). Below that is the assessed value — the number the assessor decided on. Next to it or nearby is the tax rate, usually shown as mills per dollar or as a percentage.

The bill then shows the calculation: assessed value multiplied by tax rate equals the gross tax. Below that, any exemptions are subtracted (shown as a dollar amount or a reduced assessed value). Then any credits are subtracted. The result is your net tax bill — what you actually owe.

The bill also breaks down how much of your payment goes to each entity: county, city, school district, and special districts. This shows you exactly which services your tax dollars fund. If you disagree with the assessed value shown on the bill, the bill usually includes instructions for filing an appeal and a important date for doing so.

What happens if you disagree with your assessed value

If you believe your assessed value is too high, you can file a formal challenge. The process is called an appeal, grievance, or protest, depending on your state. You must file within a set window — often 30 to 45 days after you receive your assessment notice — and you must follow your local procedure exactly.

Most jurisdictions require you to file a written form with your county assessor's office or a board of review. You will need to explain why you disagree and provide evidence: recent sales of comparable homes, a professional appraisal, documentation of property defects, or proof that similar homes in your area are assessed lower. The burden is on you to show that the assessed value is wrong, not on the assessor to prove it is right.

If the assessor or board of review denies your appeal, you may be able to appeal further to a county board or state tax court, but this usually requires hiring a lawyer and is expensive. Many people settle the matter at the first level or accept the assessment. If you win an appeal, your assessed value is reduced, which lowers your bill going forward — but you typically cannot recover taxes you already paid based on the higher value.

Frequently Asked Questions

Is my assessed value the same as my home's market value?

Not necessarily. Assessed value is an estimate of market value, but it lags behind actual market changes because assessments happen on a schedule, not continuously. If your neighborhood has boomed in the past year but your county reassesses every three years, your assessed value may be significantly lower than what your home would sell for today.

Can I lower my property tax bill by making my home look worse?

Not reliably. Assessors use public records and comparable sales, not just visual inspection. Deferred maintenance might lower your value slightly, but most assessors will not penalize you for a messy yard or peeling paint — they care about structural condition and functional obsolescence, not cosmetics.

What is the difference between property tax and school tax?

School tax is part of your property tax bill. Your total property tax goes to multiple entities, and one of them is your school district. The school district sets its own tax rate and collects it as part of your property tax bill. You cannot separate them — you pay one bill that funds schools, county services, city services, and other local entities.

Do I have to pay property tax if I own my home outright?

Yes. Property tax is owed by the owner of the land and building, regardless of whether there is a mortgage. If you have a mortgage, your lender may collect property tax as part of your monthly payment and pay it on your behalf, but you are still legally responsible for it.

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

Your county can place a lien on your property, meaning they have a legal claim against it. If you continue not to pay, the county can eventually foreclose and sell your home to recover the unpaid taxes and penalties. The timeline varies by state, but it usually takes several years of non-payment before foreclosure happens.