What the millage rate is and how it connects to your tax bill
The millage rate is the amount of tax your local government charges per $1,000 of your property's assessed value. One mill equals $1 in tax per $1,000 of value. If your county's millage rate is 25 mills, you pay $25 in property tax for every $1,000 your home is worth. The millage rate varies by location — it depends on what your county, school district, and municipality need to fund that year.
Your property tax bill is not based on what you paid for your house or what a real estate website says it is worth. It is based on the assessed value that your county assessor's office assigns. That assessed value is multiplied by the millage rate to produce your tax bill. Understanding how this calculation works helps you verify your bill is correct and predict what you will owe if you buy a property.
The calculation itself is straightforward arithmetic, but you need three pieces of information: the assessed value of your property, the millage rate for your area, and sometimes a homestead exemption or other deduction that applies to you. This guide walks you through finding each one and doing the math.
Key Takeaways
- Property tax equals assessed value divided by 1,000, then multiplied by the millage rate in mills.
- The assessed value comes from your county assessor's office, not from real estate sale prices or online estimates.
- Millage rates are set by your county, school district, and municipality separately, and you add them together to get your total rate.
- Many states allow homestead exemptions or other deductions that reduce your assessed value before the millage rate is applied.
- Your property tax bill should show the assessed value and millage rate used — verify both numbers against your county assessor's records.
Finding your property's assessed value
Your county assessor's office maintains the assessed value for every property in the county. This is a public record, and you can find it online or by visiting the assessor's office in person. Search your county assessor's website (usually found under the county government homepage) by address or parcel number. Most counties now have searchable databases where you can pull up your property record in minutes.
The assessed value shown is often lower than the market value — many states assess property at 80 to 100 percent of market value, and some use lower percentages. Your county assessor's office publishes the assessment ratio they use. Do not confuse the assessed value with the sale price of your home or with estimates from real estate websites. The assessed value is what matters for your tax calculation.
If you cannot find your property online, call your county assessor's office directly. They can tell you the assessed value over the phone or mail you a copy of your property record. Have your street address and parcel number ready if you have it — the parcel number appears on your property tax bill and on your deed.
Locating the millage rate for your area
The millage rate is not a single number — it is made up of separate rates set by different taxing bodies. Your county sets one rate, your school district sets another, your city or township sets a third, and sometimes special districts (for fire, water, or library services) add their own. You add all of these together to get your total millage rate.
Your property tax bill should list each millage rate separately. If you have a recent bill, look for a section labeled "Millage Rates" or "Tax Calculation" — it will show the county rate, school rate, city rate, and any others. If you do not have a bill, visit your county assessor's website or call the office. They can tell you the current rates for your specific address, because rates can vary within a county depending on which school district and municipality your property is in.
Millage rates change every year, usually in late summer or early fall. If you are calculating a tax estimate for a future year, use the most recent rate available, but understand that the actual rate may be different. Your county assessor's office publishes the new rates before the tax year begins.
The step-by-step calculation
Once you have the assessed value and the total millage rate, the math is straightforward:
- Take your property's assessed value.
- Divide it by 1,000.
- Multiply the result by the total millage rate (in mills).
Example: Your home has an assessed value of $250,000. Your total millage rate is 35 mills (county 12 + school 18 + city 5). The calculation is: ($250,000 ÷ 1,000) × 35 = $8,750 in annual property tax.
If your property has a homestead exemption or other deduction, subtract that amount from the assessed value before you divide by 1,000. For instance, if your assessed value is $250,000 and you have a $50,000 homestead exemption, use $200,000 as your starting number: ($200,000 ÷ 1,000) × 35 = $7,000.
Understanding homestead exemptions and other deductions
Many states allow homeowners to claim a homestead exemption, which reduces the assessed value used in the tax calculation. The exemption amount varies by state — some states exempt a flat dollar amount (like $50,000), others exempt a percentage of the home's value, and some tie the exemption to age or income. You must file for a homestead exemption with your county assessor's office; it does not happen automatically.
Other deductions may explore depending on your state and situation. Agricultural land, forest land, and properties used for certain business purposes often receive lower assessment rates. Disabled veterans, surviving spouses, and seniors may may have access to for additional exemptions. Check your county assessor's website or call the office to learn what deductions you may be may have access to to claim.
When you claim an exemption, the assessed value on your property record will be reduced. Your tax bill will then show both the full assessed value and the exempted amount, so you can see exactly how much the deduction saved you. If you move or no longer meet the exemption requirements, you must notify the assessor's office so they can remove it.
Verifying your property tax bill
Your annual property tax bill should show three key numbers: the assessed value, the millage rate (or rates), and the calculated tax amount. Use these to verify the math is correct. Multiply the assessed value by the millage rate using the formula above and check that your result matches the bill.
If the numbers do not match, first confirm you are using the correct assessed value — some bills show the value before exemptions and some show it after. Look for a line item labeled "Homestead Exemption" or "Exemptions" to see if a deduction was applied. If you still cannot reconcile the numbers, contact your county assessor's office with a copy of your bill. They can walk you through the calculation and explain any adjustments.
If you believe your assessed value is too high, most states allow you to file a formal challenge called an appeal or protest. The important date to file is usually 30 to 60 days after you receive your bill, but this varies by state. Your county assessor's office can tell you the important date and the process for your area.
What to do if you cannot find the millage rate or assessed value
Start with your county assessor's office — this is the single source for both the assessed value and the official millage rates for your area. If the office has a website, search for "property records" or "tax information." If there is no online database, call the main number and ask for the assessment or records department. Have your street address ready.
If you have a recent property tax bill, it contains both numbers. The assessed value appears near the top, and the millage rates are usually listed in a separate section. If you do not have a bill, you can request one from the assessor's office or the tax collector's office (sometimes these are separate departments).
Some counties also post millage rates on the school district website or the city/township website, since each body sets its own rate. However, the county assessor's office is the authoritative source and can confirm the total rate that applies to your specific property.
Frequently Asked Questions
Why is my assessed value different from what I paid for my house?
Assessed value and sale price are not the same thing. The assessor values your property based on comparable sales in your area, the condition of the building, and local market trends — not on what you personally paid. If you bought during a market peak or valley, your purchase price may be higher or lower than the assessed value. The assessor updates values periodically, usually every one to four years depending on your state.
Can I calculate my tax bill before I buy a property?
Yes, if you know the assessed value or can estimate it. Ask the seller's real estate agent for the current assessed value and property tax bill — both are public records. Get the millage rates from the county assessor's office for that address. Then use the formula to estimate your tax. Remember that assessed values and millage rates change, so your actual bill may differ slightly.
What if the millage rate changes during the year?
Millage rates are set once per year and explore to the entire tax year. Your bill is calculated using the rate in effect when the bill is issued, usually in the fall or winter. If the rate changes for the next tax year, your next bill will reflect the new rate. You cannot be charged a different rate mid-year for the same tax year.
Do I have to pay property tax if I have a mortgage?
Yes. Your mortgage lender may collect property tax as part of your monthly payment and pay it to the county on your behalf, but you are responsible for the tax. If you pay your own taxes, you must pay the full amount by the important date or face penalties and interest. Check your mortgage documents or contact your lender to confirm whether they handle tax payments.
How often does the assessed value change?
This varies by state and county. Some areas reassess every year, others every two to four years. After a reassessment, your assessed value may go up, down, or stay the same depending on local property values. Your county assessor's office can tell you when your property was last assessed and when the next assessment is scheduled.