What is the mill rate and how does it determine your property tax bill?

Last updated 2026-07-09

What is a mill rate, exactly?

A mill rate is your local government's price tag for one thousand dollars of assessed property value. The word "mill" comes from the Latin "millesimum," meaning one-thousandth. One mill equals $0.001, or $1 of tax for every $1,000 of assessed value. ^[1]

So when your county announces a mill rate of 20, you owe $20 for every $1,000 of assessed value on your home. A house assessed at $300,000 in a 20-mill jurisdiction owes $6,000 before any exemptions.

Mill rates are also called millage rates. You'll see both terms used interchangeably on your tax bill, in your local paper, and in state statutes. The math is identical either way.

The rate is not one single number. It's a stack. Your county, your municipality, your school district, any special assessment districts, and sometimes a community college or fire district each add their own layer. The total mill rate on your bill is the sum of all those layers. ^[2]

How do you calculate property tax from a mill rate?

Divide your assessed value by 1,000, then multiply by the total mill rate. That's your annual tax. The full formula is short.

Property Tax = (Assessed Value / 1,000) × Mill Rate

Or the same thing written differently: Assessed Value × (Mill Rate / 1,000).

Here's a worked example. Say your home's assessed value is $250,000 and your total mill rate is 24.5 mills.

$250,000 / 1,000 = $250 $250 × 24.5 = $6,125 in annual property tax

If your state uses an assessment ratio (meaning only a fraction of market value becomes the assessed value), apply the ratio first. Illinois assesses most residential property at 33.33% of market value ^[3], so a home worth $300,000 has an assessed value of $100,000 before the mill rate is applied. Georgia assesses residential property at 40% of fair market value. ^[4] Check your state's ratio before you run the numbers.

Want to check your own bill? Pull your assessed value from your most recent notice. Find the total millage rate on that same notice or your county assessor's website. Plug both into the formula. If the result doesn't match your actual bill, the difference is almost always an exemption (like a homestead exemption) reducing the taxable base, or a flat fee that isn't a mill-rate charge at all.

Some jurisdictions publish separate mill rates by property class. Commercial property often carries a higher rate than residential in the same county. Keep that in mind if you own both. ^[2]

How is the mill rate set each year?

Local governments set mill rates during their annual budget process, and they work backwards. They don't pick a rate and see what it raises. They decide how much money they need, subtract other revenue (state aid, fees, grants), then divide the remainder by the total assessed value of all taxable property in the jurisdiction. That quotient is the mill rate. ^[2]

The formula is:

Mill Rate = (Total Tax Levy Needed / Total Assessed Value of All Property) × 1,000

Because of this, your mill rate can climb even if your own assessed value never moves. It happens when your local government grows its budget, or when total assessed values across the jurisdiction fall (a smaller denominator pushes the rate up). The reverse holds too. Fast growth in a community's tax base can pull the mill rate down.

This is why homeowners get blindsided. Your house didn't change. The neighborhood didn't change. But the school board approved a capital project, the fire district added staff, or the county faced a pension shortfall, and your rate jumped 1.5 mills. That's a separate problem from your assessment, and appealing your assessment won't fix it.

Most states require governing bodies to hold public hearings before adopting a final rate. Florida's TRIM (Truth in Millage) law requires taxing authorities to mail every property owner a written notice each August showing the proposed rate, what it means in dollars for that specific parcel, and when the public hearing is scheduled. ^[5] Other states run similar truth-in-taxation statutes under different names.

What are typical mill rates across the United States?

Mill rates swing wildly from state to state, and county to county inside the same state. A lot of that gap reflects assessment ratios. A state that assesses at 10% of market value needs a much higher nominal rate to raise the same money as one that assesses at 100%.

The Lincoln Institute of Land Policy's Fiscally Standardized Cities database gives the cleanest apples-to-apples comparison. It converts different state systems into effective tax rates (annual tax as a percentage of market value). ^[6] The table below shows approximate effective rates for a sample of major markets, using Lincoln Institute data.

City / County	Approx. Effective Rate (% of market value)
Detroit, MI	2.50%+
Milwaukee, WI	2.20%+
Chicago (Cook County), IL	1.90%+
Houston (Harris County), TX	1.80%+
Philadelphia, PA	1.35%
New York City, NY	0.80% to 1.00%
Los Angeles (LA County), CA	0.70% to 0.75%
Honolulu, HI	0.28% to 0.35%

Those percentages look small until you put them on real houses. A 0.75% effective rate on a $900,000 Los Angeles home is $6,750 a year. The same rate on a $120,000 Detroit home is $900, but Detroit's actual rate runs more than triple that, so the Detroit owner pays far more per dollar of value.

For the actual published mill rates in your area, go straight to your county assessor or auditor's website. Many post annual rate sheets by taxing district. The Cook County Assessor's office publishes levy and rate detail that breaks down exactly which taxing bodies charge what. Maricopa County in Arizona publishes a similar breakdown by jurisdiction. Los Angeles County and San Diego County post annual secured tax rate books.

What is the difference between mill rate and effective tax rate?

The mill rate is the nominal rate applied to your assessed value. The effective tax rate is your actual annual tax as a percentage of your home's full market value. People confuse them constantly. The gap between the two comes from assessment ratios and exemptions.

Here's why that matters. New Jersey has some of the highest effective property tax rates in the country, routinely above 2% of market value. ^[7] New Jersey also assesses at 100% of true market value in theory, so its nominal mill rate and effective rate track closely. California is the opposite story. Proposition 13 caps assessed value growth at 2% a year for long-held properties ^[8], so a homeowner who bought in 1995 may carry an assessed value that's a sliver of market value. California's nominal mill rate (around 10 mills in most counties) looks moderate, but the effective rate on a freshly purchased home is much higher than on the identical house next door bought 25 years ago.

Use effective rates when you want to compare tax burdens across cities or states. Use the nominal mill rate applied to your assessed value when you want to calculate or verify your own bill.

Can your assessed value be wrong even if the mill rate is correct?

Yes, and it's the most common reason homeowners overpay. The mill rate comes out of a public vote or budget process, so it's hard to dispute. Your assessed value comes from the assessor, and it can absolutely be wrong.

Assessors revalue on a cycle, often every one to four years depending on the state. Between cycles, values get extrapolated from sales data using mass appraisal models. Those models don't know about your unpermitted addition, your basement that flooded twice, or the fact that the comparable sales they pulled sit in a better school zone. Errors are routine.

If your assessed value looks inflated, you have the right to appeal. That process is separate from anything the mill rate does. You're arguing the assessor got your value wrong, not that the rate is unfair (you generally can't appeal the mill rate; it's a legislative function). A win lowers your taxable assessed value, which then gets multiplied by whatever rate applies.

Put real numbers on it. If your mill rate is 22 mills and your assessed value is overstated by $40,000, you're overpaying $880 a year. Over five years with no reassessment, that's $4,400. Worth fighting for.

The TaxFightBack DIY appeal kit walks through how to gather comparable sales evidence and file the forms yourself, without handing a contingency firm 25% to 40% of your first year's savings.

In specific counties like Bexar County, Texas, Gwinnett County, Georgia, or Lake County, Illinois, those links go to guides on how each local assessor handles appeals, including deadlines and filing requirements.

Why does your mill rate change from year to year?

Four things move a mill rate. Any one of them can push your rate up or down with no change to your property at all.

First, budget increases. School districts, counties, and cities raise spending regularly. Every dollar of new spending that other revenue doesn't cover gets spread across the tax base as a higher mill rate.

Second, budget cuts or one-time windfalls. A state aid package, a big federal grant, or a spending cut can pull the rate down for a year.

Third, changes in the overall tax base. If a lot of new construction went up in your county, total assessed value rises, and that bigger denominator can push the mill rate down even on the same budget. If a major employer closes and large commercial properties lose value, the base shrinks and rates rise.

Fourth, voter-approved levies. Bonds for school construction, library expansions, and similar projects add dedicated mill rate increments that show up as separate line items, often for a fixed term (say, 20 years for a bond). These get called voted levies or special levies to separate them from the general operating levy.

States vary on how much room local governments have to raise rates without asking voters. Many cap how much the operating mill rate can climb in a single year without a referendum. Colorado's Taxpayer's Bill of Rights (TABOR) requires voter approval for tax increases above a growth-and-inflation index. ^[9]

How do exemptions interact with the mill rate?

Exemptions cut your taxable assessed value before the mill rate ever touches it. They don't change the rate. They shrink the base the rate multiplies against.

The most common one is the homestead exemption, available in most states for primary residences. It knocks a flat dollar amount or a percentage off your assessed value. Georgia's basic homestead exemption removes $2,000 from assessed value for school and county purposes. ^[10] Florida's takes $50,000 off the assessed value for qualifying homeowners (the first $25,000 applies to all taxing authorities; the second $25,000 applies to non-school millage). ^[5]

Work it through. Say your assessed value is $200,000, you have a $50,000 Florida homestead exemption, and your total mill rate is 18 mills:

Taxable value = $200,000 minus $50,000 = $150,000 Tax = $150,000 / 1,000 × 18 = $2,700

Without the exemption you'd owe $3,600. The rate never moved. The taxable base did.

Senior, disability, veteran, and agricultural exemptions all work the same way. Check with your county assessor to confirm which ones you qualify for. Some need to be applied for every year; others renew automatically once granted. Counties like Madison County and Bibb County in Georgia each add local exemptions on top of the state ones, so reading both the state statute and your county's rules matters.

Where can you find the current mill rate for your property?

Start with your most recent tax bill or assessment notice. Most jurisdictions print the mill rate, often broken down by taxing district, right on the bill.

No bill handy? Your county assessor's or auditor's website is next. Search for "mill rate" or "millage rate" or "tax rate" plus your county name. Most publish an annual rate sheet, sometimes called a tax rate book or levy rate schedule, usually as a PDF.

For Georgia counties like Coweta County and Cherokee County, the Tax Assessor's office publishes digest and millage information directly. In Missouri, St. Louis County posts rate information alongside its personal property and real property tax records.

Want a national view or a way to compare your rate against other areas? The Lincoln Institute of Land Policy's Significant Features of the Property Tax database and its Fiscally Standardized Cities tool are the most reliable public sources. ^[6]

One caution. The mill rate you find may be a total, or it may be split into components. Make sure you're using the total (all taxing districts combined) when you calculate your expected bill. Using just the county rate while missing the school district rate, which is often the single largest component, will make your estimate far too low.

Is a high mill rate always a sign of high property taxes?

No. The mill rate works on assessed value, and assessed values get set differently everywhere. A state that assesses at 10% of market value needs a rate ten times higher than a state that assesses at 100% to produce the same effective burden.

This is why comparing raw mill rates across state lines is close to meaningless. A 100-mill rate in a state that assesses at 10% produces the same effective rate as a 10-mill rate in a state that assesses at 100%. Both come out to a 1% effective rate on market value.

Inside a single state where every county uses the same assessment rules, comparing mill rates makes more sense. A county at 30 mills carries higher effective taxes than one at 20 mills, assuming the assessment ratios and exemption structures match.

The honest metric for comparing tax burdens across places is the effective tax rate: annual tax divided by market value. You can also use median annual taxes against median household income. The Tax Foundation publishes annual state-by-state property tax burden estimates, though its methodology weights by owner-occupied housing units and differs from the Lincoln Institute approach. ^[11] Neither source is perfect. Both are transparent about their methods, which beats most real estate websites that show tax figures without saying what they measure.

What should you do if you think your property tax bill is too high?

First, figure out whether the problem is the mill rate or your assessed value. The mill rate is what it is; you almost certainly can't appeal it. Your assessed value is fair game.

Get your property record card from the assessor's office (most post these online now). Check the basic facts: square footage, number of bathrooms, year built, whether it lists a finished basement you don't have. Errors in physical characteristics are the easiest wins.

Then pull comparable sales. Find three to five homes in your neighborhood that sold in the six to twelve months before your assessment date, similar to yours in size, age, and condition, and check what they sold for. If your assessed value (adjusted for your state's assessment ratio) beats those sale prices, you have a case.

Most counties let you file an informal appeal first, before the formal hearing. That conversation with the assessor's office costs nothing and sometimes settles the issue with no further paperwork.

If the informal route stalls, a formal appeal before your local board of review or board of equalization is next. Deadlines are strict and vary by state. Miss the window and you usually wait a full year for the next cycle. Check your assessment notice for your jurisdiction's specific deadline, or look it up on your county assessor's website.

The TaxFightBack appeal kit includes the comparable sales worksheets and filing instructions for the most common state appeal formats, so you're not building the paperwork from scratch.

Frequently asked questions

What is a mill rate in property tax?

A mill rate is the property tax charged per $1,000 of assessed value. One mill equals $1 of tax per $1,000 of value. To find your annual bill, divide your assessed value by 1,000 and multiply by the total mill rate. A $250,000 assessed value at 20 mills produces a $5,000 annual tax bill.

How do I calculate my property tax using the mill rate?

The formula is (Assessed Value / 1,000) × Mill Rate = Annual Property Tax. Find your assessed value on your assessment notice and your total mill rate on your tax bill or county assessor's website. If your state uses an assessment ratio below 100%, apply that ratio to your market value first to get the assessed value, then run the calculation.

What is a typical mill rate in the United States?

There's no single typical rate, because mill rates depend on local budgets and how each state sets assessed values. Effective tax rates (annual tax as a percentage of market value) run from around 0.28% in Hawaii to over 2.5% in parts of Michigan and New Jersey. Comparing raw mill rates across states misleads unless you account for different assessment ratios.

Who sets the mill rate?

Local governing bodies set mill rates: your county commission, city council, school board, and any special districts each adopt a levy. They decide how much money they need, subtract non-property-tax revenue, and divide by the total assessed value of all property in their jurisdiction. The result is their mill rate. Most states require a public hearing before adoption.

Can I appeal my mill rate if I think it is too high?

No. The mill rate is a legislative act by your local governing bodies, not an appraisal of your specific property. You can vote against incumbents, testify at public budget hearings, or lobby elected officials, but there's no formal appeal for the rate itself. What you can appeal is your assessed value, which directly affects how much tax you owe at whatever rate applies.

Why did my property tax bill go up if my assessed value stayed the same?

Your mill rate went up. This happens when local governments raise their budgets, when the overall tax base in your jurisdiction shrinks (fewer properties or lower values spread the burden over a smaller base), or when voters approve a new levy for schools, bonds, or infrastructure. A higher mill rate means a higher bill even with your assessed value unchanged.

What is the difference between mill rate and millage rate?

They're the same thing. Both terms describe the tax rate as dollars per $1,000 of assessed value. "Millage rate" is more common in the South and Southeast. "Mill rate" is more common in the Northeast and Midwest. Your tax bill may use either term, or it may just say "tax rate" without either word.

How do exemptions affect the mill rate calculation?

Exemptions reduce your taxable assessed value before the mill rate is applied, not the rate itself. A $50,000 homestead exemption on a $200,000 assessed value leaves $150,000 taxable. At a 20-mill rate, that saves you $1,000 a year versus paying on the full $200,000. Apply your exemptions to find the taxable base before multiplying by the mill rate.

Is the mill rate the same for commercial and residential property?

Not always. Some states and municipalities set different mill rates by property class, and commercial property often carries a higher rate. Even where a single nominal rate applies, commercial property is typically assessed at a higher fraction of market value than residential, producing a higher effective rate. Check your local rate schedule for the classification that fits your property.

Where can I find the mill rate for my specific county or city?

Your annual property tax bill or assessment notice is the fastest source, and it usually lists each taxing authority and its rate. If you need the current rate outside billing season, check your county assessor's, auditor's, or treasurer's website and search for "millage rate," "mill rate," or "tax rate schedule." Many counties publish a PDF rate book each year.

How often does the mill rate change?

Most jurisdictions set a new mill rate every year during their budget cycle. The rate can shift annually based on budget decisions, changes in total assessed value across the jurisdiction, voter-approved levies, and state-mandated adjustments. A rate that was 18 mills three years ago might be 21 mills today with no change to your property at all.

What is a voted levy and how does it appear on my mill rate?

A voted levy is a mill rate increment approved by voters, usually to fund specific items like school construction bonds or library operations. It shows up as a separate line item on your tax bill and adds to your total mill rate for a fixed term (often 10 to 30 years for bond levies). Once the bond is paid off, that increment drops off unless voters renew it.

Does a higher assessed value always mean a higher tax bill?

If the mill rate and your exemptions hold steady, a higher assessed value means a higher bill in direct proportion. But if your value rises because the whole market rose, the assessor may trim the mill rate slightly when the total tax base grows faster than the levy. In practice, most homeowners watch their assessed value and their tax bill rise together over time.

What is the note about end mill feed rate calculators I keep seeing?

That's a different kind of "mill." An end mill feed rate calculator is a machining tool used in manufacturing to set cutting speeds for end mills (rotary cutting tools). It has nothing to do with property taxes. If you searched for a mill rate calculator and landed on machining content, search specifically for "property tax mill rate calculator" or use the formula on this page.

Sources

1. Merriam-Webster Dictionary, definition of 'mill': The word 'mill' derives from the Latin millesimum, meaning one-thousandth; one mill equals $0.001.
2. International Association of Assessing Officers (IAAO), Property Assessment Valuation: Mill rates are the sum of multiple overlapping taxing jurisdictions; the rate is derived by dividing the levy needed by total assessed value.
3. Illinois Department of Revenue: Illinois assesses most residential property at 33.33% of market value.
4. Georgia Department of Revenue, Property Tax Guide: Georgia assesses residential property at 40% of fair market value.
5. Florida Department of Revenue, Truth in Millage (TRIM) Program: Florida's TRIM law requires taxing authorities to mail each property owner a notice each August showing proposed millage rates and dollar impact; the standard homestead exemption is $50,000.
6. Lincoln Institute of Land Policy, Fiscally Standardized Cities Database: The Lincoln Institute's FiSC database provides effective property tax rates expressed as annual tax as a percentage of market value across major U.S. cities.
7. Tax Foundation, Facts and Figures: How Does Your State Compare?: New Jersey has effective property tax rates routinely above 2% of market value, among the highest in the nation.
8. California State Board of Equalization, Proposition 13 Overview: California's Proposition 13 caps annual increases in assessed value at 2% per year for properties that have not changed ownership.
9. Colorado Legislative Council Staff, TABOR Overview: Colorado's Taxpayer's Bill of Rights (TABOR) requires voter approval for tax revenue increases above a growth-and-inflation index.
10. Georgia Department of Revenue, Homestead Exemptions: Georgia's basic homestead exemption removes $2,000 from assessed value for school and county tax purposes.
11. Tax Foundation, Annual State-by-State Property Tax Burden Estimates: The Tax Foundation publishes annual property tax burden estimates by state weighted by owner-occupied housing units.