The Basic Formula: Assessed Value Times Tax Rate

Your property tax bill comes from one straightforward multiplication: the assessed value of your property times the tax rate set by your local government. The assessed value is not what you paid for the house or what it would sell for today — it is a value assigned by your county or local assessor's office, usually lower than market price. The tax rate is a percentage or dollar amount per thousand dollars of assessed value, set by your city, county, school district, and other local bodies that depend on property tax revenue.

The math itself is straightforward, but the two numbers that go into it — assessed value and tax rate — come from different places and change on different schedules. Understanding where each one comes from helps you read your bill and know when and why it might change.

Key Takeaways

  • Your property tax equals the assessed value of your home multiplied by the local tax rate, both of which are set by government bodies, not by you or your lender.
  • The assessed value is usually 80 to 100 percent of market value and is recalculated every one to three years depending on your state, not every time you sell.
  • The tax rate is expressed as a percentage or as dollars per thousand dollars of assessed value and combines rates from your city, county, school district, and other local services.
  • Your bill can change even if you do nothing, because either the assessed value or the tax rate — or both — can change on a schedule set by your state.
  • You can usually see your assessed value and tax rate on your property tax bill or on your county assessor's website, and you have the right to challenge the assessed value if you believe it is wrong.

What the Assessed Value Is and How It Gets Set

The assessed value is the dollar amount your local assessor assigns to your property for tax purposes. It is not the same as the purchase price, the appraised value for a mortgage, or the estimated market value. Most states require the assessed value to be a percentage of fair market value — often 80 to 100 percent, depending on the state — but some states use different methods entirely.

Your assessor's office determines this value by looking at comparable sales in your area, the condition and age of your building, the size of the lot, and other features. They do not reassess every property every year. Instead, most states reassess on a cycle: every one, two, or three years depending on where you live. Some states reassess only when a property changes hands. A few states reassess annually. You can find out your state's reassessment schedule by calling your county assessor's office or checking their website.

When a reassessment happens, your assessed value may go up, go down, or stay the same. If it goes up significantly, your tax bill will rise even if the tax rate does not change. This is one of the two main reasons your property tax bill can jump from year to year.

How the Tax Rate Is Built From Multiple Local Bodies

The tax rate on your property bill is not a single number set by one government. Instead, it is the sum of rates set by several overlapping local bodies: your city or township, your county, your school district, and often special districts for fire, water, or other services. Each body sets its own rate based on its budget needs and the total assessed value of property in its area.

Tax rates are usually expressed in one of two ways. Some jurisdictions show a percentage — for example, 1.2 percent of assessed value. Others show a rate per thousand dollars of assessed value — for example, $12 per $1,000 of assessed value, which is the same as 1.2 percent. Your property tax bill should show the breakdown of which portion goes to the city, which to the county, which to schools, and so on.

When a local body needs more revenue — because it is building a new school, hiring more police, or covering a budget shortfall — it may raise its tax rate. This affects all property owners in that jurisdiction. You will see the rate increase on your next bill, even if your assessed value did not change. This is the second main reason your property tax bill can rise year to year.

Putting the Numbers Together on Your Bill

The calculation on your actual bill looks like this: take your assessed value, multiply it by the combined tax rate, and the result is your annual property tax. If your assessed value is $200,000 and the combined tax rate is 1.2 percent, your tax is $2,400 per year. If the rate is expressed as $12 per $1,000, you divide $200,000 by 1,000 to get 200, then multiply by $12 to get $2,400 — the same answer.

Your bill may also include other charges: fees for water, sewer, or trash collection; special assessments for local improvements like new sidewalks; or charges for code violations or unpaid prior-year taxes. These are separate from the property tax calculation itself, but they appear on the same bill. Read the bill carefully to see which charges are property tax and which are something else.

Why Your Bill Changes Even When You Do Nothing

Many homeowners are surprised when their property tax bill rises without any action on their part. This happens because either the assessed value or the tax rate — or both — changed on a schedule set by your state and local government, not by you.

If your assessed value went up at the last reassessment, your bill will be higher. If your school district or city raised its tax rate to cover a new budget, your bill will be higher. In some states, assessed values are capped or increase by a set percentage each year even if the property's market value rises faster — this is called a homestead exemption or assessment cap, and it limits how much your bill can jump. Other states have no cap, so your bill can rise sharply if the market value of your home increases rapidly.

You can find out which of these two factors — assessed value or tax rate — caused your bill to change by comparing your current bill to the previous year's bill. Your assessor's office can also tell you whether a reassessment happened and what your new assessed value is.

How to Find Your Assessed Value and Tax Rate

Your property tax bill itself should show both the assessed value and the tax rate, usually near the top or in a summary section. If your bill does not clearly show these numbers, call your county assessor's office and ask for them. You can also visit your county assessor's website — most counties now have online databases where you can search by address and see the assessed value, tax rate, and recent tax history.

Knowing these two numbers lets you understand your bill and predict roughly what next year's bill might be. If you know a reassessment is coming in your state, you can estimate whether your assessed value might change. If you follow local news about school or city budgets, you may hear about tax rate changes before they appear on your bill.

Challenging Your Assessed Value

If you believe your assessed value is too high — because your home is in worse condition than comparable homes, or because the assessor made an error — you have the right to challenge it. The process and important date vary by state, but most states allow you to file a formal objection or appeal with your county assessor or a local board of review.

To challenge successfully, you usually need to show that the assessed value is higher than the fair market value of similar homes in your area. You can gather this evidence by looking at recent sales of comparable homes, getting an independent appraisal, or pointing out errors in the assessor's records — for example, if they listed your house as having four bedrooms when it has three. Contact your county assessor's office to learn the important date for filing an appeal in your area and what documents you need to submit.

Frequently Asked Questions

Is my property tax the same as my mortgage payment?

No. Your mortgage payment covers principal and interest to your lender. Property tax is a separate bill paid to your local government. If you have a mortgage, your lender may collect property tax from you each month as part of an escrow account and pay it on your behalf, but the tax itself is not part of the mortgage.

Why is my assessed value different from what I paid for my house?

Assessed value is set by the assessor using a formula based on comparable sales and property features, not on what you paid. Your purchase price is one data point the assessor may use, but it is not the only one. The assessed value may be higher or lower than your purchase price depending on market conditions and the assessor's methods.

Can my property tax bill go down?

Yes, if either your assessed value or the tax rate decreases. Assessed values can drop if the market declines or if you successfully challenge the value. Tax rates can drop if a local government reduces its budget, though this is less common. You can also reduce your bill by may have access to for an exemption, such as a homestead exemption or exemption for seniors or veterans, if your state offers them.

What happens if I do not pay my property tax?

Your local government can place a lien on your property, meaning it has a legal claim against it. If you do not pay for long enough, the government can foreclose and sell your home to recover the unpaid tax and penalties. The timeline varies by state, but it is usually several years. If you are struggling to pay, contact your assessor's office or local government to ask about payment plans or hardship programs.

How often does the assessed value change?

This depends on your state. Some states reassess every year, others every two or three years, and a few only when the property is sold. You can find your state's reassessment schedule by contacting your county assessor's office or checking their website. Even in years when a full reassessment does not happen, your assessed value may be adjusted slightly based on new information.