Understanding Property Tax Rates and Millage

Property taxes are the primary source of revenue for most local governments, funding everything from public schools and police departments to road maintenance and libraries. But the way they are calculated can seem like a foreign language — filled with terms like "mill rate," "assessed value," "equalization ratio," and "effective rate."

To truly understand how much you're paying and why, you need to understand the relationship between two key numbers: your assessed value and your local tax rate. Once you grasp these fundamentals, the mystery of your property tax bill disappears.

1. Market value vs. assessed value

These two numbers are often confused, but they serve very different purposes:

Market value is the price your home would likely sell for on the open market today. It is determined by supply and demand, comparable recent sales in your area, the condition of your home, and broader economic conditions. Real estate agents and online tools like Zillow estimate market value, but the definitive market value is whatever a willing buyer pays a willing seller in an arm's-length transaction.

Assessed value is a separate number assigned to your property by the local tax assessor specifically for the purpose of taxation. In some jurisdictions, the assessed value is set at 100% of the market value. In others, it may be a fraction — for example, many counties in New York assess properties at only 5% to 20% of market value, while South Carolina assesses owner-occupied homes at just 4% of market value.

The ratio between assessed value and market value is called the assessment ratio (or "equalization ratio" or "level of assessment"). Understanding this ratio is crucial because the tax rate is applied to the assessed value, not the market value. A home with a market value of $400,000 and an assessment ratio of 50% has an assessed value of $200,000 — and your property tax is calculated based on that $200,000 figure.

2. What is a mill rate?

In many parts of the United States and Canada, property tax rates are expressed in "mills" or a "millage rate." The word comes from the Latin millesimum, meaning "thousandth."

If your town has a mill rate of 20 mills, and your home is assessed at $300,000, your tax calculation looks like this:

• Divide assessed value by 1,000: $300,000 / 1,000 = 300
• Multiply by the mill rate: 300 × 20 = $6,000

Your annual property tax bill would be $6,000. This is the equivalent of a 2% effective tax rate (since $6,000 / $300,000 = 0.02 or 2%).

Mill rates are sometimes expressed in decimal form. A mill rate of 20 mills can also be written as 0.020 or 20.000. To convert a mill rate to a percentage, simply divide by 10: 20 mills = 2.0%.

Your total mill rate is usually composed of several individual levies stacked together. For example, a total mill rate of 45 might break down as:

• County government: 8 mills
• City/township: 12 mills
• School district: 20 mills
• Library district: 2 mills
• Fire protection district: 3 mills

Each of these taxing entities sets its own levy independently. This is why two homes in the same county but different school districts can have very different tax bills, even if their assessed values are identical.

3. Effective tax rates

Because assessment ratios and local levies vary so wildly from town to town, economists and tax analysts often look at the effective tax rate to compare tax burdens fairly across jurisdictions. The effective tax rate is a simple calculation:

For example, if your home's market value is $350,000 and you pay $4,200 in property taxes per year, your effective tax rate is $4,200 / $350,000 = 0.012, or 1.20%.

The effective rate eliminates the confusion created by varying assessment ratios. Two homes may have very different mill rates and assessment ratios but end up with similar effective tax rates. This is why our calculator at MyTaxHike relies heavily on average effective tax rates — they provide the most accurate and comparable estimates regardless of the confusing local math your municipality uses on paper.

4. Why tax rates change from year to year

Your local government sets an annual budget that determines how much revenue it needs from property taxes. To fund that budget, they calculate the total assessed property value of all taxable properties in the jurisdiction (the "tax base"), and then set the mill rate just high enough to generate the required revenue.

This means that if property values across the entire town increase by 20% during a reassessment, the local government might actually lower the mill rate to avoid collecting more revenue than their budget requires. In some states, this is a legal requirement — referred to as a "revenue-neutral rate" or "rollback rate."

However, the relationship between your assessment change and your tax bill depends on how your property's value compares to the average change in the jurisdiction:

• Your value rose faster than the town average: Even if the mill rate drops, your share of the total tax base grew, so your tax bill goes up.
• Your value rose at the same pace as the town average: Your tax bill stays roughly the same (assuming no budget increase).
• Your value rose slower than the town average: Your tax bill might actually decrease slightly.

This is an important nuance that many homeowners miss. A rising assessment doesn't automatically mean a proportionally higher tax bill — it depends on the context of the entire community's property values.

5. How to find your local mill rate

Your current mill rate (or tax rate) is publicly available. Here are the most common ways to find it:

• Your tax bill: Most property tax bills itemize the rate and show the individual levies.
• Your county assessor's website: Often published in an annual report or tax rate schedule.
• Your municipality's budget documents: Local governments publish their adopted budgets, which include the approved mill rate.
• State department of revenue: Many states publish a database of all local tax rates by county or municipality.

If you can't find your exact local rate, our property tax calculator uses statewide average effective rates, which give you a close approximation.

6. Property tax exemptions: a brief overview

Most jurisdictions offer exemptions that reduce your taxable assessed value or provide a credit against your tax bill. Common exemptions include:

• Homestead exemption: Reduces the taxable value of your primary residence. Available in many US states, with amounts varying from $5,000 to $50,000 or more.
• Senior citizen exemption: Additional reduction for homeowners over a certain age (typically 65). May be income-qualified.
• Veteran exemption: Reduction for military veterans, particularly those with service-connected disabilities.
• Disability exemption: For homeowners with qualifying disabilities.
• Agricultural/open space: Reduced rates for land used for farming or preserved as open space.

Exemptions are not automatically applied — you usually need to apply for them through your assessor's office. Many homeowners miss thousands of dollars in savings simply because they never applied for exemptions they were eligible for. Read our complete guide to property tax exemptions for more details.

7. How tax rates compare across states

Property tax burdens vary enormously across the United States. States like New Jersey (effective rate ~2.49%), Illinois (~2.23%), and New Hampshire (~2.18%) consistently rank among the highest. On the other end, Hawaii (~0.28%), Alabama (~0.40%), and Colorado (~0.51%) have some of the lowest effective rates.

These differences reflect not just local policy choices but also how states fund their services. States with no income tax (like Texas and New Hampshire) tend to rely more heavily on property taxes. States with robust income and sales tax revenue (like Hawaii) can keep property tax rates lower.

For a detailed state-by-state breakdown using the data in our calculator, see our property tax rates by state comparison guide.