Mill rate meaning: what it is and how it sets your tax bill

Last updated 2026-07-09

What does mill rate mean in property tax?

A mill rate is a tax rate expressed in thousandths of a dollar. The word "mill" comes from the Latin "millesimum," meaning one-thousandth. One mill equals $1 of tax for every $1,000 of assessed value, which is the same as $0.001 per dollar of value ^[1].

Your county, school board, and other taxing authorities each pass their own mill rate. Those rates stack into one total composite rate. Your bill is that composite rate multiplied by your home's assessed value, after any exemptions come off.

This is not an obscure technicality. The mill rate is the one lever a government pulls to raise or lower what you owe in a given year, and it moves independently of what your home is actually worth.

How do you calculate property tax from a mill rate?

The math is short. The formula is:

Annual Tax = (Assessed Value / 1,000) x Mill Rate

Say your home's assessed value is $250,000 and your total mill rate is 24 mills. Your bill is ($250,000 / 1,000) x 24 = $250 x 24 = $6,000.

Some jurisdictions apply the rate to "taxable value" instead of full assessed value. Taxable value is assessed value minus any exemptions (homestead, senior, veteran, and so on). If that same $250,000 home carries a $50,000 homestead exemption, taxable value drops to $200,000, and the tax becomes ($200,000 / 1,000) x 24 = $4,800. That $1,200 gap comes entirely from the exemption. The rate never moved ^[2].

A handful of states assess property at a fixed fraction of market value. Georgia is the clearest example. Assessed value there is legally set at 40% of fair market value under O.C.G.A. § 48-5-7 ^[3]. So a Georgia home with a $300,000 market value has an assessed value of $120,000 before any exemption. Check your state's assessment ratio before you run a single number.

Scenario	Assessed Value	Mill Rate	Annual Tax
Base case	$250,000	24	$6,000
With $50,000 exemption	$200,000	24	$4,800
Higher mill rate, same value	$250,000	30	$7,500
Lower assessed value	$180,000	24	$4,320

What is a typical mill rate across the United States?

There is no clean national "typical" mill rate, and any single figure falls apart without context. The Lincoln Institute of Land Policy tracks effective tax rates, which fold assessment ratios and mill rates into one comparable number. Its data puts the median effective rate across large U.S. cities near 1.0% to 1.5% of market value, with a spread from under 0.5% in parts of Hawaii and Alabama to over 3% in parts of Illinois, New Jersey, and New York ^[4].

In raw mill terms, here is a rough sense of the range:

State / Area	Approximate Total Mill Rate Range
Hawaii	3 to 9 mills (low because assessed values run high)
Alabama	5 to 20 mills
Georgia	20 to 45 mills
Illinois (suburban Cook County)	60 to 100+ mills
New Jersey	150 to 250+ mills
Connecticut	20 to 75 mills

A high mill rate is not automatically a bad deal. New Jersey's 200-mill rates apply to assessed values that often sit at 80% to 100% of market value. Georgia's 30-mill rates apply to values pegged at 40% of market value. Comparing mill rates state to state without the assessment ratio tells you almost nothing ^[4].

For how this plays out in specific counties, see Cook County tax assessor tax bill or Maricopa property tax.

Who actually sets the mill rate, and when?

No single office sets your mill rate. Several overlapping taxing districts each set their own levy, and those rates stack. A typical homeowner sees components from the county, the municipality, the school district, a community college district, a fire district, a library district, and sometimes a special assessment district.

Each body runs a budget cycle, usually in summer or fall. It figures out how much revenue it needs, subtracts other income, and the remainder falls to property taxes. That amount divided by the total assessed value of all property in the district is that body's mill rate for the year.

So your total mill rate changes every year. Your assessment can hold flat and your bill can still climb if any one of those bodies needs more money. That is why bills go up in years when no reassessment notice ever shows up.

Most states require a public hearing and a formal vote before rates lock in. California's Proposition 13 caps the base rate at 1% of assessed value at purchase, with voter-approved bonds layered on top ^[5]. Texas Truth in Taxation law forces taxing units to publish and advertise any rate that would pull in more revenue than the prior year ^[6].

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

These two numbers describe the same burden from different angles, and people mix them up constantly.

The mill rate is a nominal rate applied to assessed value. The effective tax rate is annual taxes paid divided by actual market value. The gap between them depends entirely on the assessment ratio.

Here is the trap. A jurisdiction with a 50-mill rate and a 40% assessment ratio produces an effective rate of 50 x 0.40 / 1,000 = 0.020, or 2.0% of market value. A different jurisdiction with a 20-mill rate and a 100% assessment ratio produces 20 / 1,000 = 0.020, also 2.0%.

Same real burden. Wildly different-looking mill rates.

Comparing the tax cost of two places? Use the effective rate. Calculating your own bill? Use the mill rate plus your jurisdiction's assessment ratio. The Lincoln Institute's Fiscally Standardized Cities database is the best free tool for side-by-side effective rate comparisons across major metros ^[4].

For state context, Los Angeles County property tax and San Diego property tax both show how California's Prop 13 framework creates a very low nominal rate but effective rates that swing based on when a home last changed hands.

How does an assessment reduction actually lower your tax bill?

The mill rate is fixed at the government level. You cannot negotiate it and you cannot appeal it. What you can appeal is the assessed value your local assessor put on your property ^[7].

Win an appeal, cut your assessed value, and your tax falls in lockstep. At a 24-mill rate, every $10,000 you knock off assessed value saves $240 a year. In a high-mill area like suburban Chicago, call it 80 mills, that same $10,000 cut saves $800 a year, and the savings repeat until the next reassessment resets your value.

That is why appeals pay off most in high-mill jurisdictions. The fixed rate acts as a multiplier on every dollar of over-assessment.

Want to run the numbers before you file? DIY tools like the TaxFightBack Appeal Kit let you build the comparable-sales argument and estimate exactly what a given reduction saves at your real mill rate, without handing 30% to 40% of the savings to a contingency firm.

Two things drive your bill: the rate and the base. You only control the base.

Can a government raise the mill rate without a vote?

It depends on state law, and the rules are all over the map.

Some states cap annual increases without a supermajority vote or a referendum. Michigan's Headlee Amendment forces local governments to roll their mill rates back when assessed values rise faster than inflation, so rising values do not hand government a quiet windfall ^[8]. Colorado's Gallagher Amendment (now repealed) did something similar by adjusting assessment ratios.

Other states have almost no formal cap. A school board in New Jersey or Connecticut can raise its slice of the mill rate through its annual budget without a separate tax referendum, though voters in some states can reject school budgets outright.

Texas took a stricter route. Under the Texas Property Tax Code, if a taxing unit adopts a rate more than 3.5% above its "no-new-revenue rate" (for most units), voters can trigger an automatic rollback election ^[6]. The 2019 law that did this, Senate Bill 2, dropped the rollback trigger from 8% to 3.5% for most entities ^[6].

California's base 1% rate is locked in by Proposition 13, but voter-approved general obligation bonds ride on top, which is why a California county's total effective rate often lands between 1.1% and 1.3% even with the base capped ^[5].

Where do you find your property's mill rate?

Your property tax bill or assessment notice is the fastest place to look. Most jurisdictions now have to list each taxing body's rate separately, so you can see exactly how the total gets built.

For the official source, work through these in order:

1. Your county assessor or county auditor's website. Most post the current year's rates as a PDF or a table. Gwinnett County, for example, publishes its millage rates broken out by city and school district every year. See Gwinnett County tax assessor for direct links to the rate tables.

2. Your state department of revenue or taxation website. Many states pull all county and municipal rates into one annual report, which makes comparison easy.

3. Your state legislature's fiscal notes or research arm. Connecticut's Office of Policy and Management, for instance, publishes a full list of mill rates for all 169 Connecticut municipalities each year ^[9].

If you are in Georgia (40% assessment ratio territory), Bibb County tax assessor, Cherokee County tax assessor, Coweta County tax assessor, and Madison County tax assessor all post their digest and millage information online. The exact URL shifts with each budget cycle, so start at the assessor's homepage.

What happens to the mill rate when property values spike?

This is where the politics turn interesting. When a mass reassessment pushes assessed values up across a whole jurisdiction, the same revenue target divided by a bigger tax base produces a lower mill rate. In theory, homeowners break even. In practice, three things get in the way.

First, taxing bodies often read rising values as room to spend more rather than a reason to hold rates flat. The rate drops, but not in proportion to the value jump, so homeowners pay more in real dollars.

Second, even a proportional rate cut fails the homeowner whose property rose faster than average. If your home jumped 30% while the district average rose 15%, your bill climbs even as the mill rate falls.

Third, some jurisdictions run long reassessment cycles. Cook County reassesses by township on a three-year cycle. Other states reassess every four to six years. During a hot market, values sit stale on the low side, and one sudden reassessment lands as sticker shock.

The Lincoln Institute found that through the 2021 to 2023 run-up in home prices, effective property tax rates actually fell in most states because assessed values trailed market prices, a temporary break expected to reverse as reassessments catch up ^[4]. Nobody has clean data on exactly when the catch-up hits each county, so watch your assessment notice for a year or two after a hot market.

For Texas, Bexar County tax assessor covers how the annual appraisal cycle meets the homestead cap, which limits how fast a primary residence's appraised value can rise (currently 10% per year under Texas Tax Code § 23.23) ^[6].

How does the mill rate interact with exemptions?

Exemptions cut the assessed value before the mill rate touches it. The rate itself never moves. But in a high-mill area, even a small exemption is worth real money.

Take the homestead exemption. Georgia's standard county homestead exemption is $2,000 off assessed value ^[3]. At a 30-mill rate, that saves $60 a year. Not much. But Georgia school districts and cities often stack their own exemptions, and some counties offer elderly or disability exemptions worth $10,000 to $50,000 off assessed value, which at 30 mills is $300 to $1,500 a year.

In Illinois, the General Homestead Exemption cuts equalized assessed value by $10,000 ^[10]. At Cook County's composite rate, which often runs 6% to 9% of assessed value in suburban townships, that $10,000 saves $600 to $900 a year. The Senior Assessment Freeze Exemption freezes your EAV at the level when you first qualified, shielding all future assessment growth from tax.

Texas raised its school district homestead exemption to $100,000 off appraised value starting in 2023 (up from $40,000 under Proposition 4) ^[6]. At a typical Texas school rate near 100 mills, that is $10,000 x 0.100 = $1,000 saved a year from that one exemption alone.

The mill rate tells you what each dollar of exemption is worth. That is one of the most useful things knowing it does for you.

Is a high mill rate always a red flag for a property buyer?

No. You need the full picture: the mill rate, the assessment ratio, and what services the rate pays for.

A school district at 60 mills with top-rated schools can be a better buy than a district at 20 mills with underfunded ones, depending on what you value. For Lake County property tax in Illinois, the headline mill rates look alarming until you count what the roads, schools, and parks actually deliver.

The number a buyer needs is one thing: what is my actual annual tax bill on this specific property? Run it yourself using the current total mill rate times the expected assessed value, and check whether your state reassesses at purchase price. Do not lean on the seller's current bill if they hold exemptions you will not qualify for.

Missouri buyers, take note. St. Louis County personal property tax is a reminder that Missouri taxes personal property (vehicles, boats) at mill rates too, often higher than real estate, which changes your total cost in a way out-of-state buyers miss.

The cleanest way to say what a mill rate tells a buyer: it is a multiplier, and you need both sides of the multiplication before it means anything.

What should you do if your mill rate went up this year?

Verify the new rate first on your county's official site or your tax bill. Confirm which taxing body drove the increase. A school levy hike is a different animal from a county general fund hike, and the remedy (if any exists) differs too.

You cannot appeal the mill rate. What you can do:

• Vote and show up in the budget process for the taxing body in question.
• File a formal objection or a referendum petition if your state allows rollback elections. Texas and Michigan, among others, have these.
• Turn to what you control: make sure your assessed value is right. An over-assessed home plus a rising mill rate is a double hit. A winning appeal cuts your tax at the new, higher rate.

If you are in a reassessment year and your assessment rose alongside the mill rate, that is the moment to move. Most counties give you 30 to 90 days from the assessment notice to file. Miss that window and you wait a full cycle. That is a full year of savings gone, at the new, higher rate.

The TaxFightBack Appeal Kit walks through the evidence you need (comparable sales, uniform assessment arguments, income-approach analysis for income property) so you file the appeal yourself and keep every dollar of the reduction.

The mill rate is the government's lever. The assessed value is yours.

Frequently asked questions

What does one mill equal in dollars?

One mill equals $1 of property tax per $1,000 of assessed value, or $0.001 per dollar of value. If your assessed value is $200,000 and your mill rate is 1, you owe $200. At 25 mills you owe $5,000. The formula is always: (assessed value divided by 1,000) multiplied by the mill rate.

Is mill rate the same as tax rate?

They measure the same thing on different scales. A mill rate of 20 mills equals a tax rate of 2.0% applied to assessed value. The confusion comes from assessment ratios: if assessed value is only 40% of market value, a 20-mill rate produces an effective rate on market value of just 0.8%. Always confirm what value the rate is applied to before comparing.

How often does the mill rate change?

Most taxing jurisdictions set a new mill rate every year during their budget process, usually in summer or fall before the new tax year starts. The rate can rise or fall. Some states cap how far it can rise without a voter referendum, such as Michigan's Headlee Amendment and Texas's 3.5% no-new-revenue threshold under Senate Bill 2 (2019).

Can I appeal my mill rate?

No. The mill rate is set by a legislative body (county commission, school board, city council) through a public budget process, not by the assessor. You cannot appeal it at the property tax board of review. What you can appeal is your assessed value, which directly reduces your tax at whatever the current mill rate happens to be.

What is a millage rate versus a mill rate?

The two terms mean exactly the same thing. Millage rate is the form used in many Southern and Midwestern states, while mill rate is more common in New England and parts of the West. Both refer to property tax expressed as dollars per $1,000 of assessed value, and the math is identical.

Why did my property tax bill go up if my assessed value didn't change?

The mill rate rose. Your bill is the product of two numbers: your assessed value and the composite mill rate. If one taxing body in your district, often the school district, raised its levy while your value held flat, your total bill still climbs. Check your tax bill for a line-by-line rate breakdown to find which body raised its rate.

How do I find the mill rate for my specific county?

Start with your county assessor's or county auditor's website. Most post the current year's rate table by taxing district. Your state department of revenue often compiles all county rates in one annual report. Connecticut's Office of Policy and Management, for example, publishes a full municipal mill rate list each year. Your actual tax bill also shows each component rate.

Does Georgia's 40% assessment ratio affect how mill rates compare to other states?

Yes, a lot. Under O.C.G.A. § 48-5-7, Georgia assesses residential property at 40% of fair market value. A 30-mill Georgia rate applied to 40% of value produces an effective rate of 1.2% of market value. That same 1.2% effective rate in a state that assesses at 100% of value would show as only 12 mills. Never compare Georgia mill rates directly to full-value states.

What is a no-new-revenue tax rate in Texas?

Texas law defines the no-new-revenue rate as the mill rate that would produce the same total property tax revenue as the prior year, adjusted for new construction. If a taxing unit adopts a rate more than 3.5% above this threshold (for most units), voters can trigger an automatic rollback election under the Texas Property Tax Code as amended by Senate Bill 2 in 2019.

How does Proposition 13 in California affect the mill rate?

California's Proposition 13 (1978) caps the base property tax rate at 1% of assessed value statewide. Local voter-approved general obligation bonds add rates on top of that base, typically 0.1% to 0.3%, so most California homeowners pay a total effective rate between 1.0% and 1.3%. The 1% base rate cannot be exceeded without a two-thirds voter supermajority.

What is an effective tax rate and how is it different from a mill rate?

The effective tax rate is annual taxes paid divided by the property's actual market value, expressed as a percentage. The mill rate is the nominal rate applied to assessed value, which may be only a fraction of market value. A 50-mill rate on 40% of market value produces a 2.0% effective rate, identical to a 20-mill rate on 100% of market value. Use effective rates for cross-state comparisons.

How much does reducing my assessed value save per year in dollar terms?

Savings equal the assessed value reduction multiplied by the mill rate, divided by 1,000. At a 30-mill rate, a $20,000 assessment reduction saves $600 a year. At an 80-mill rate (common in suburban Illinois), that same reduction saves $1,600 a year. High-mill-rate jurisdictions make every dollar of over-assessment more expensive, which is exactly why filing an appeal there pays off.

Do exemptions reduce the mill rate or the assessed value?

Exemptions reduce assessed value (or taxable value), not the mill rate. The rate stays fixed. That means an exemption's dollar value to you scales directly with your mill rate. A $10,000 exemption saves $100 at a 10-mill rate but $800 at an 80-mill rate. Stacking multiple exemptions (homestead, senior, veteran, disability) in a high-mill area can produce thousands in annual savings.

Sources

1. Merriam-Webster Dictionary, 'mill' (sense relating to taxation): One mill equals one-thousandth of a dollar, derived from Latin millesimum
2. Illinois Department of Revenue, Property Tax Overview: Taxable value is assessed value minus applicable exemptions, and the mill rate is applied to taxable value
3. Georgia Code § 48-5-7 (Official Code of Georgia Annotated), Property assessment at 40% of fair market value: Georgia residential property is assessed at 40% of fair market value; homestead exemption reduces assessed value by $2,000 for county taxes
4. Lincoln Institute of Land Policy, Fiscally Standardized Cities database and 50-State Property Tax Comparison: Median effective property tax rates across large U.S. cities range from under 0.5% to over 3% of market value; during 2021-2023 price appreciation, effective rates fell in most states as assessed values lagged market prices
5. California Board of Equalization, Proposition 13 Overview: Proposition 13 caps the base property tax rate at 1% of assessed value; voter-approved bonds add to the total rate
6. Texas Comptroller of Public Accounts, Property Tax Basics and Truth in Taxation: Texas Senate Bill 2 (2019) lowered the rollback threshold to 3.5% above the no-new-revenue rate for most taxing units; Texas Tax Code § 23.23 caps homestead appraisal increases at 10% per year; 2023 Proposition 4 raised the school homestead exemption to $100,000
7. National Taxpayers Union Foundation, Property Tax Appeal Guide: Property owners can appeal assessed value but cannot appeal mill rates, which are set by legislative bodies
8. Michigan Department of Treasury, Headlee Amendment Overview: Michigan's Headlee Amendment requires local governments to roll back mill rates if assessed values rise faster than inflation, preventing a windfall tax increase without voter approval
9. Connecticut Office of Policy and Management, Municipal Mill Rates: Connecticut OPM publishes annual mill rates for all 169 Connecticut municipalities
10. Cook County Assessor's Office, Exemptions Overview: Illinois General Homestead Exemption reduces equalized assessed value by $10,000; Senior Assessment Freeze Exemption freezes EAV at the year of qualification