Your property tax is calculated by multiplying your home's assessed value by your local tax rate
The basic formula is straightforward: assessed value × tax rate = property tax owed. Your local assessor determines the assessed value, and your local government sets the tax rate. Neither number is the same everywhere — a house worth $300,000 in one county may have a different assessed value than an identical house in another county, and tax rates vary by state, county, and sometimes by school district.
The assessed value is not always the same as what you paid for the house or what it would sell for today. Assessors use methods like comparing recent sales of similar homes, calculating replacement cost, or using income data if the property is rental. The tax rate is expressed as a percentage or as dollars per $1,000 of assessed value — for example, 1.2% or $12 per $1,000.
Key Takeaways
- Your property tax bill comes from the assessed value set by your county or local assessor multiplied by the tax rate set by your local government.
- Assessed value is not the same as purchase price or market value — assessors use sales comparisons, cost methods, or income methods to arrive at it.
- Tax rates vary by location and often include separate levies for schools, county services, and municipalities, which you can see itemized on your bill.
- You can usually find your assessed value and tax rate on your property tax bill, your assessor's website, or by contacting your local assessor's office directly.
- If you believe your assessed value is too high, most states allow you to file a formal challenge called an assessment appeal or tax assessment protest.
How assessors determine your home's assessed value
Assessors use three main methods to arrive at assessed value, and the method used depends on the property type and local practice. The sales comparison approach looks at recent sales of similar homes in your area — same size, condition, lot, and location — and adjusts for differences. If a comparable home sold for $320,000 and yours has an extra bedroom, the assessor might adjust upward.
The cost approach calculates what it would cost to rebuild your home from scratch, then subtracts depreciation for age and wear. This method is common for newer homes or unique properties where few comparables exist. The income approach applies mainly to rental properties and is based on the income the property generates.
Most assessors use a combination of these methods and update assessed values on a cycle — every year in some places, every three to five years in others. Your assessment notice will tell you when your property was last assessed and when the next assessment is due. If you have made major improvements like adding a room or a new roof, the assessor may conduct a physical inspection and adjust the value upward.
Where tax rates come from and what they cover
Your tax rate is set by your local government — usually the county, city, or township — and often includes multiple separate levies. A single property tax bill may include charges for county services, municipal services, schools, fire districts, library districts, and special improvement districts. Each of these entities sets its own rate, and they are added together to create your total rate.
The largest portion typically goes to schools. In many states, school funding depends heavily on property tax revenue, so school districts set their own rates within limits set by state law. County and municipal rates cover roads, courts, sheriff services, and administration. Special districts — for water, sewer, fire, or library services — add their own levies if you live in their boundaries.
Your property tax bill should itemize each levy so you can see how much goes to schools, how much to the county, and how much to other services. If you want to know why your rate increased, contact your county assessor's office or the specific district — they can tell you whether the increase came from a higher assessed value, a higher tax rate, or both.
How to find your assessed value and tax rate
Your property tax bill lists both your assessed value and your tax rate, usually near the top or in a summary section. The bill shows the calculation: assessed value multiplied by the rate equals the amount due. If you have lost your bill or want to check the information, your county assessor's office maintains public records of all assessed values and tax rates.
Most counties now publish assessor data online. Search "[your county] assessor" or "[your county] property appraiser" to find the website. You can usually search by address or parcel number and see the assessed value, the breakdown of tax rates, and sometimes the sales history and property details the assessor used. If the website does not have what you need, call the assessor's office directly — they are required to provide this information to the public.
Some counties charge a small fee to pull a detailed property record or assessment report, but basic information like assessed value and tax rate is free. If you are buying a home, the title company or real estate agent can also provide the current assessed value and estimated tax amount before closing.
Why your assessed value may differ from your home's market value
Your assessed value and your home's market value can be very different, and this is normal. Market value is what a buyer would pay today; assessed value is what the assessor determined for tax purposes, often based on older sales data or a formula. In a rising market, assessed values often lag behind market values because assessments are not updated every year. In a falling market, assessed values may be higher than what the home would sell for.
Some states use a fractional assessment system, where assessed value is intentionally set at a percentage of market value — for example, 50% or 80%. This is done to keep tax bills lower while still funding services. Your assessment notice should state whether your assessed value is the full value or a fraction of it.
Additionally, assessed value does not account for personal factors like your income, how long you have owned the home, or whether you live in it. Two identical homes on the same street will have the same assessed value even if one owner is retired and the other is working. This is why property tax is considered regressive — it does not adjust to ability to pay.
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 and timeline vary by state, but most states allow homeowners to file an assessment appeal or tax assessment protest within a set window — often 30 to 45 days after you receive your assessment notice. Your assessment notice should include the important date and instructions for filing.
To file an appeal, you typically submit a written request to your county assessor or board of assessment appeals, depending on your state's process. Include your property address, parcel number, and the reason you believe the value is wrong. You may need to provide evidence — recent appraisals, comparable sales data, photos of damage or needed repairs, or documentation that the assessor made a factual error like listing an extra bedroom you do not have.
If the assessor agrees with you, they will lower the value and you may receive a refund or credit on your next bill. If you disagree with the assessor's response, you can usually appeal to a board of assessment appeals or a county board of equalization. Some states allow a further appeal to tax court, though this usually requires hiring an attorney and is expensive.
How exemptions and abatements affect your tax bill
Even if your assessed value is correct, you may owe less tax if you are may have access to to an exemption or abatement. Exemptions reduce the assessed value itself — for example, a homestead exemption might reduce your assessed value by a set amount if you live in the home as your primary residence. Abatements reduce the tax rate or the amount owed, usually for a set period.
Common exemptions include homestead exemptions for owner-occupied homes, exemptions for seniors or disabled persons, exemptions for veterans, and exemptions for agricultural land. Abatements are often offered for new construction or home improvements to encourage development. Your state and local government determine which exemptions and abatements are available in your area.
You must usually file a form to claim an exemption — it does not happen automatically. Contact your county assessor's office to ask which exemptions you may be may have access to to and what documentation you need to provide. Missing the filing important date can cost you a year or more of tax savings, so ask about important date when you inquire.
Frequently Asked Questions
Why did my property tax bill go up if I did not make any improvements?
Your bill can increase if your assessed value increased, if the tax rate increased, or both. Assessed values can rise because the assessor updated the value based on recent sales in your area, or because your county reassessed all properties. Tax rates increase when local governments raise them to fund services. Check your bill to see whether the increase came from a higher value, a higher rate, or both, then contact your assessor or local government for details.
Can I lower my property tax by lowering my home's assessed value?
Yes, if you can show the assessed value is too high. You can file an assessment appeal if you have evidence — an independent appraisal, recent comparable sales, or proof the assessor made an error. You cannot straightforward ask for a lower value without evidence. If your home needs major repairs, that can justify a lower value, but you must document it.
Is my property tax bill the same every year?
No. Your bill can change if your assessed value changes, if the tax rate changes, or if you gain or lose an exemption. Some states cap how much the assessed value can increase in a single year, so your bill may be more stable than in states without caps. Check your bill each year to see what changed.
How do I know if my tax rate is fair compared to other counties?
Tax rates vary widely by location because they depend on local government spending and state funding formulas. A higher rate does not necessarily mean unfair — it may reflect higher spending on schools or services. You can compare rates by looking at your bill and similar bills from other counties, but context matters. Contact your county assessor or local government if you want to understand why your rate is what it is.
What if the assessor made a mistake on my property record?
Contact your assessor's office when ready. Common errors include listing an extra room, wrong lot size, or wrong year built. The assessor will investigate and correct the record if an error is found. This may lower your assessed value and your tax bill. You do not need to file a formal appeal for a factual error — a phone call or letter to the assessor is usually enough.