How your property tax bill is determined
Your property tax bill comes from multiplying your home's assessed value by your local tax rate, then subtracting any exemptions you may have. The assessed value is not what you paid for the house or what it would sell for today — it is a value set by your county or municipal assessor, usually lower than market value. The tax rate (called the millage rate in some states) is set by your local government and expressed as a dollar amount per $1,000 of assessed value, or sometimes as a percentage.
The formula looks like this: (Assessed Value ÷ 1,000) × Millage Rate = Annual Tax, minus any exemptions. If your home is assessed at $200,000 and your millage rate is 12 per $1,000 of value, your tax before exemptions would be $2,400 per year. The actual bill you receive reflects this calculation, and it changes when either the assessed value or the tax rate changes.
Key Takeaways
- Your assessed value is set by the county or municipal assessor and is usually lower than your home's market value or purchase price.
- The tax rate (millage rate) is set by your local government and varies by county, city, and school district.
- Your bill is calculated by multiplying assessed value by the tax rate, then subtracting exemptions like homestead or senior exemptions if you may have access to.
- Assessed values are typically updated every 1 to 5 years depending on your state, and you can request a reassessment if you believe the value is wrong.
- Tax rates change annually based on local government budgets, so your bill can increase or decrease even if your assessed value stays the same.
Who sets the assessed value and how often it changes
Your county or municipal assessor's office determines the assessed value of your property. They do this by reviewing sales of comparable homes in your area, the condition and age of your home, lot size, and any improvements you have made. This process is called mass appraisal because assessors value thousands of properties at once, not individually like a real estate appraiser would.
Assessed values are updated on a schedule that varies by state. Some states reassess every year; others do it every 3 to 5 years. A few states use a fractional assessment system where the assessed value is a percentage of market value (for example, 50 percent). You can find your state's reassessment cycle and assessment ratio by contacting your assessor's office or checking your county's website.
When your home is reassessed, the assessor may increase, decrease, or keep the value the same. A reassessment does not automatically mean your tax bill will go up — it depends on whether the assessed value changed and whether the tax rate changed. If your assessed value went up but the tax rate went down, your bill might stay the same or even decrease.
What the tax rate is and why it varies by location
The tax rate is the percentage or per-$1,000 amount your local government charges on assessed property value. It is set by your city council, county commission, or school board — whoever controls the budget for services you receive through property taxes. Different jurisdictions have different rates because they have different costs and different revenue sources.
Your property tax bill usually includes taxes for multiple entities: your county, your city or township, your school district, and sometimes special districts like fire protection or water management. Each of these has its own tax rate, and they are added together to create your total rate. A home in one county might have a total rate of 10 per $1,000 of value, while a home in a neighboring county might be 15 per $1,000 — even if the assessed values are identical.
Tax rates change every year as local governments adjust their budgets. If a school district needs more money, it may raise its portion of the rate. If a county has a budget surplus, it may lower its rate. You can see the breakdown of your tax rate by entity on your property tax bill or by asking your assessor's office.
Exemptions that reduce your tax bill
An exemption reduces the assessed value that the tax rate is applied to, which lowers your bill. The most common exemptions are homestead exemptions (for primary residences), senior exemptions, disability exemptions, and veteran exemptions. Some states also offer exemptions for agricultural land, historic properties, or solar installations.
Homestead exemptions are available in most states and typically reduce the assessed value by a fixed dollar amount or percentage — for example, $50,000 off the assessed value, or 10 percent of the value. To claim a homestead exemption, you usually must own the home and live in it as your primary residence. You file a form with your assessor's office, usually once, though some states require you to renew it annually.
Senior, disability, and veteran exemptions vary widely by state and sometimes by county. Some offer a percentage reduction; others offer a fixed dollar amount. may be able to access requirements differ — age thresholds for seniors range from 55 to 75 depending on the state, and disability or veteran status must usually be documented. Contact your assessor's office to learn which exemptions you may be may have access to to and what documents you need to claim them.
How to find your assessed value and tax rate
Your assessed value and tax rate appear on your property tax bill, which you receive once or twice per year depending on your state. The bill shows the assessed value, the tax rate (or rates for each entity), the calculation, and the amount due. If you have lost your bill or want to check the value outside of billing season, you can look it up online through your county assessor's website or visit the assessor's office in person.
Most county assessor websites have a searchable database where you can enter your address or parcel number and see the assessed value, property description, exemptions on file, and sometimes the tax calculation. Some sites also show you the assessed values of nearby homes so you can compare. If you cannot find it online, call your assessor's office — they can give you the information over the phone or mail you a property record card.
Your tax bill also breaks down the tax rate by entity. For example, it might show 4.5 per $1,000 for the county, 3.2 per $1,000 for the school district, and 1.8 per $1,000 for the city, for a total of 9.5 per $1,000. If you want to know why the rate changed from last year, contact the entity that raised it — usually the school district or county — and ask for the reason.
What to do if you think your assessed value is wrong
If you believe your assessed value is too high, you can request a reassessment or file a formal appeal. The process and timeline vary by state, but most states allow you to challenge the value within a certain window — often 30 to 60 days after you receive your bill or after the new assessment is mailed to you.
Before you file an appeal, gather evidence that supports a lower value: recent appraisals, sales prices of comparable homes in your area, photos of damage or needed repairs, or documentation of property defects. The assessor will review your evidence and either adjust the value or uphold it. If you disagree with the result, you can usually appeal to a county board of review or equalization board, and in some cases to tax court.
Appeals are free to file, though hiring a property tax consultant or attorney to help you build your case costs money. If your appeal is successful and your assessed value is lowered, your tax bill for the following year will be lower. Some states also allow you to claim a refund of overpaid taxes from the current year if the value is reduced mid-year.
How changes in your home affect the assessed value
When you make improvements to your home — adding a room, finishing a basement, installing a new roof, or upgrading systems — the assessor may increase the assessed value to reflect the improvement. The assessor learns about improvements through building permits filed with your city or county. If you pull a permit for work, the assessor's office is usually notified and will inspect the property at the next reassessment cycle.
Not all improvements trigger a value increase. Routine maintenance like painting, replacing flooring, or fixing a roof typically does not change the assessed value. Major structural additions or upgrades usually do. If you are concerned that an improvement will raise your assessment significantly, you can ask the assessor's office whether the work will trigger a reassessment before you start.
Conversely, if your home has lost value because of damage, deferred maintenance, or neighborhood decline, you can request that the assessed value be lowered. You will need to provide evidence — photos, repair estimates, or a recent appraisal — to support the request. The assessor will review your evidence and may adjust the value downward.
Frequently Asked Questions
Why is my assessed value different from what I paid for my house?
Assessed value and purchase price are two different things. The assessed value is set by the assessor based on comparable sales and property characteristics, while the purchase price is what you and the seller agreed to. Assessed values are usually lower than market value, and they may be lower or higher than what you paid depending on when you bought and how the market has changed since.
Can I lower my property tax bill without appealing the assessed value?
Yes, if you have not already claimed all the exemptions you are may have access to to. Homestead, senior, disability, and veteran exemptions can reduce your assessed value and lower your bill. Contact your assessor's office to ask which exemptions apply to you and what documents you need to claim them. Some exemptions require you to file a form only once; others must be renewed annually.
How often should I check my assessed value?
Check it whenever you receive a new tax bill or when you know a reassessment has occurred in your county. If you made major improvements to your home, check it after the next reassessment cycle to see if the value increased. If you think the value is wrong, you can check it anytime through your assessor's website or by calling the office.
What happens if I disagree with the assessor's decision after I appeal?
Most states allow you to appeal the assessor's decision to a county board of review or equalization board. The board will review your evidence and the assessor's reasoning and make a final decision. If you still disagree, some states allow further appeal to tax court, though this usually requires an attorney and costs money.
Does my tax bill include anything other than property tax?
Your bill may include property tax, but it can also include special assessments for local improvements (like a new road or sewer line), homeowners association fees if you live in a planned community, or water and sewer charges. Read your bill carefully to see what each line item covers. If you are unsure, contact your assessor's office or the entity that sent the bill.