How Property Taxes Are Calculated: Assessments, Mill Rates, and Appeals

$707 Billion Collected from Property Owners in 2022

The U.S. Census Bureau reported that state and local governments collected approximately $707 billion in property taxes during fiscal year 2022. Property taxes represent the single largest revenue source for local governments, funding schools, police and fire departments, road maintenance, parks, and public libraries. The average American homeowner paid $3,901 in property taxes that year, but the range is enormous—from under $1,000 in parts of Alabama and West Virginia to over $12,000 in New Jersey and Connecticut.

Despite paying this bill every year, most homeowners cannot explain how it is calculated.

The Two Components: Assessed Value and Tax Rate

Every property tax bill is the product of two numbers: the assessed value of the property and the tax rate set by local taxing authorities. The formula is straightforward:

Property Tax = Assessed Value × Tax Rate

Assessed value is not the same as market value. Most jurisdictions apply an assessment ratio to the market value. If a home has a market value of $400,000 and the jurisdiction uses a 60% assessment ratio, the assessed value is $240,000. The tax rate is then applied to that assessed value.

Mill Rates and How Taxing Authorities Set Them

The tax rate is often expressed in mills. One mill equals one-tenth of one cent, or $1 per $1,000 of assessed value. A 25-mill rate means a homeowner pays $25 for every $1,000 of assessed value. Multiple taxing jurisdictions typically levy separate mill rates on the same property—the county, the municipality, the school district, and sometimes special districts for libraries, fire protection, or water management.

How the rate is determined each year:

• Local governing bodies (city councils, school boards, county commissions) adopt annual budgets
• They calculate how much revenue is needed beyond other sources (state aid, fees, federal grants)
• The total needed revenue is divided by the total assessed value of all taxable property in the jurisdiction
• The resulting number becomes the mill rate

If a school district needs $50 million and the total assessed property value in the district is $5 billion, the school district mill rate is 10 mills. This process repeats for each taxing entity.

The Property Assessment Process

County or municipal assessors determine property values. Methods vary by jurisdiction but generally follow three standard appraisal approaches:

• Sales comparison approach: The most common method for residential property. The assessor compares the subject property to recent sales of similar properties in the area, adjusting for differences in size, condition, and features.
• Cost approach: Estimates what it would cost to replace the structure, subtracts depreciation, and adds land value. Used primarily for unique or new properties.
• Income approach: Used for commercial and rental properties. Calculates value based on the income the property generates, using capitalization rates.

Most jurisdictions reassess properties on a cycle—annually in some states, every 2 to 5 years in others. Between reassessments, values may be adjusted using market indices or remain fixed until the next scheduled reassessment.

Exemptions That Reduce the Tax Bill

Homestead exemptions are the most widely available. Florida, for example, offers a $50,000 homestead exemption on primary residences. On a home assessed at $300,000, this reduces the taxable value to $250,000, saving the homeowner roughly $1,000 to $1,500 annually depending on the local mill rate.

Exemptions must be applied for. They are not automatic. Many eligible homeowners miss them simply because they never filed the paperwork.

How to Appeal a Property Tax Assessment

Property owners who believe their assessment is too high can file an appeal. Success rates vary, but data from several major counties shows that 30% to 50% of appeals result in some reduction.

The appeal process typically follows these steps:

• Review the assessment notice for errors—wrong square footage, incorrect number of bedrooms or bathrooms, misclassified property type
• Research comparable sales in the area to determine whether the assessed value exceeds actual market value
• File a formal appeal with the local board of equalization or assessment review board within the statutory deadline (often 30 to 90 days from the assessment notice)
• Present evidence at a hearing—comparable sales data, independent appraisals, photographs of property condition issues
• If the local appeal fails, most states allow further appeal to a state tax tribunal or court

Common grounds for a successful appeal:

• Factual errors in the property record (wrong lot size, non-existent improvements listed)
• Comparable properties assessed at significantly lower values
• Recent independent appraisal showing a lower market value
• Property damage or deterioration not reflected in the assessment

Why Property Taxes Vary So Dramatically by Location

New Jersey's effective property tax rate averages 2.23% of home value. Hawaii's averages 0.32%. The difference stems from how each state funds its obligations. States with no income tax (like Texas, at a 1.68% effective rate) tend to rely more heavily on property taxes. States with robust income and sales tax revenues can keep property taxes lower.

School funding is the primary driver. In most states, local property taxes provide 30% to 60% of public school funding. Districts with high property values can fund schools at lower tax rates. Districts with lower property values must levy higher rates to generate equivalent revenue per student—a structural inequality that has generated litigation in nearly every state.

Property taxes are local, personal, and consequential. Understanding how your bill is calculated is the first step toward knowing whether you are paying the right amount.

This article is for informational purposes only and does not constitute financial advice.