Assessed value is the number your county uses to calculate your property tax bill. It is not the same as market value. Market value is roughly what your home would sell for today. Your assessed value is the figure printed on the tax roll. In many places, the two numbers stay close. However, they can also drift far apart. As a result, you may be paying tax on a number that is too high. This guide explains the difference in plain, simple English.
What Assessed Value Means
Your assessed value is the value your local government assigns to your property for tax purposes. A county assessor or appraisal district sets it. They look at recent home sales, your lot, your square footage, and any upgrades. Then they place a number on the tax roll. That number is your assessed value. The International Association of Assessing Officers (IAAO) publishes the standards many assessors follow.
Market value is different. It is what your home would likely sell for on the open market today. For example, a home might sell for $300,000. That is its market value. However, its assessed value on the tax roll could be higher or lower. Many states use an “assessment ratio.” That ratio is a set percentage of market value. So the assessed value may be only part of the full market value.
In most cases, your assessor sends a yearly notice. It lists your assessed value for the year. Rates and values reset each year. As a result, the number can change, sometimes sharply. Always read that notice when it arrives.
How It Works, Step by Step
Here is the basic math in plain terms. First, the assessor sets your assessed value. Next, your county sets a tax rate, often called a mill rate (the tax per $1,000 of value). Then they multiply the two. That gives your yearly bill, minus any exemptions you qualify for. The Tax Foundation and the Lincoln Institute of Land Policy both track how these rates vary widely by state and county.
The table below shows a simple, made-up example. These figures are illustrative only. Your own rate, ratio, and exemption vary by county and school district. Confirm your real numbers with your county assessor.
| Step | Illustrative Figure |
|---|---|
| Market value (likely sale price) | $300,000 |
| Assessment ratio (set by state) | 80% |
| Assessed value (300,000 × 80%) | $240,000 |
| Homestead exemption (example) | −$40,000 |
| Taxable value | $200,000 |
| Mill rate (tax per $1,000) | $15 |
| Yearly tax (200 × $15) | $3,000 |
Notice that the bill starts from the assessed value, not the $300,000 sale price. The exemption then lowers the taxable value. Typically, a smaller taxable number means a smaller bill. Your county assessor can show you the exact ratio and exemptions for your area.
Why Assessed Value Matters for Your Bill
The assessed value is the engine behind your whole tax bill. If it is too high, your bill is too high. For example, say your assessor lists your home at $260,000. However, similar homes nearby sell for $220,000. That gap is a warning sign. Your assessed value may be inflated. As a result, you could be paying more than your fair share.
Many homeowners never check this. The bill arrives, and they simply pay it. Yet an error in your assessed value follows you every single year. The U.S. Census Bureau (census.gov) shows that property tax is a major cost for most owners. So even a small error can add up over time.
Your state Department of Revenue or Taxation website explains your local rules. It also lists the exemptions you may qualify for. In most cases, checking your assessed value is free. It only costs a little of your time.
What to Do With This
Start by reading your yearly assessment notice closely. Find your assessed value on it. Then compare it to what similar homes near you have sold for. Your county assessor’s website often lists recent sales. If your assessed value looks too high, you may have a case to appeal.
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Next, check the details on your record. Assessors sometimes list the wrong square footage or bedroom count. For example, a “finished basement” that is really unfinished can raise your number. You can ask the assessor to fix plain errors. Many homeowners find mistakes this way.
Finally, ask about every exemption. You may qualify for a homestead, senior, veteran, or disability exemption. However, each one has its own deadline. Deadlines vary by county and reset each year. Confirm the exact exemption and deadline with your county assessor before you assume anything.
Frequently Asked Questions
Is assessed value the same as what my house is worth?
No. Assessed value is a taxable number set by your assessor. Market value is what a buyer would likely pay. In many states, the assessed value is only a set percentage of market value.
Why did my assessed value jump this year?
Values reset yearly. Rising home sales in your area can push it up. A remodel or added square footage can too. Your assessment notice should explain the change, and your assessor can walk you through it.
Can I lower my assessed value?
You cannot change it yourself. However, you can appeal it if it looks too high. You show recent sales of similar homes or point out errors on your record. Each county has its own appeal deadline.
Does a higher sale price raise my neighbor’s taxes too?
It can influence the whole area over time. Assessors look at nearby sales to set values. So one strong sale may nudge the assessed value on similar homes. This varies by local rules.
Where do I confirm my real numbers?
Go straight to your county assessor or appraisal district website. It is the official source for your assessed value, ratio, and exemptions. Your state Department of Revenue site explains the wider rules.
See your state’s real numbers
Property tax is the most local tax there is, so the details depend on where you live. See your state’s median rate, typical bill, exemptions, and appeal deadline in one place.
Lowering your tax bill? Check your home insurance too.
Property tax isn’t the only home cost worth a second look. Many homeowners are overpaying for home insurance without knowing it — comparing quotes is a fast way to keep more of your money.
Sources & How to Verify
The figures and rules on this page come from official and authoritative sources. Property tax rates, median bills, and exemption amounts reset every year and vary by state, county, and school district — so always confirm the current figure, any exemption, and any deadline with your county assessor before you act. We are an independent educational resource, not a government agency or a tax-appeal service, and this page is not legal, tax, or financial advice.
- Tax Foundation: taxfoundation.org — property taxes by state & county
- U.S. Census Bureau: census.gov — median property tax paid and home values
- Lincoln Institute of Land Policy: lincolninst.edu — property-tax research and the 50-state data
- IAAO (assessment standards): iaao.org — how assessors are supposed to value property
- Your county assessor & state Department of Revenue: search “[your county] assessor” for your exact rate, exemptions, and appeal deadline
Content last reviewed July 2026. If you notice an outdated figure, please contact us.
Related Guides
- How to Appeal & Lower Your Property Taxes
- Exemptions & Relief
- Property Tax Basics
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- Property Tax by State
- Property Tax Glossary
Informational only — not legal, tax, or financial advice. Know Property Tax is an independent educational resource, not a government agency, a county assessor, a law firm, or a tax-appeal service, and this page does not provide legal, tax, or financial advice. Property tax rates, median bills, exemption amounts, and deadlines change every year and vary by state, county, and school district, and any estimate is illustrative only. Always confirm your rate, any exemption, and any deadline with your county assessor and a licensed professional before you act.