Assessed value of property: what it is and how to find yours

Last updated 2026-07-09

What is the assessed value of a property?

Assessed value is the number your county or municipal assessor puts on your property to calculate how much property tax you owe. It isn't the same as market value, though the two are related. Market value is what a willing buyer pays a willing seller. Assessed value is what the government decides to tax.

Most states run a formula: assessed value equals market value multiplied by an assessment ratio. That ratio swings hard from place to place. In California, most homes are assessed at 100% of their last purchase price under Proposition 13 ^[1], then capped at a 2% annual increase. In many Midwestern counties, the ratio sits closer to 50% of market value. In New York City, Class 1 residential properties (one- to three-family homes) are assessed at 6% of market value, while Class 4 commercial properties can hit 45% ^[2].

The formula matters because your tax bill is not "assessed value times your tax rate." It's usually "assessed value minus any exemptions, times the millage rate." Every link in that chain can be wrong, and each one is a separate thing you can challenge.

How is assessed value different from market value and appraised value?

These three terms cause more confusion than almost anything else in property tax. Here's how they actually differ.

Market value is the estimated sale price. Appraised value is a licensed appraiser's formal opinion of market value, produced for a mortgage lender using sales comparisons, income analysis, or replacement cost. Neither one comes from the government.

Assessed value comes from the assessor, usually through a mass appraisal model that runs every property in a jurisdiction through the same algorithm. Mass appraisal is fast and cheap. It also misses the quirks that make your house yours: a cracked foundation, a bad floor plan, power lines humming over the backyard. Those quirks are exactly why assessments get it wrong often enough to make an appeal pay off.

Concept	Who produces it	Used for
Market value	Real estate market (buyers/sellers)	Sale price negotiations
Appraised value	Licensed appraiser	Mortgage underwriting
Assessed value	County/municipal assessor	Property tax calculation
Taxable value	Assessor after exemptions	Actual tax bill

A note on taxable value. Some states, including Michigan and Texas, cap how fast assessed value can climb each year. In Michigan, the "taxable value" cannot increase more than 5% or the rate of inflation (whichever is less) until the property sells, even if assessed value shoots up faster ^[3]. Two neighbors in identical houses can pay wildly different taxes based only on how long each has owned the place.

How do you find the assessed value of a property online?

The fastest route is your county assessor's or auditor's website. Every county in the United States has to keep public property records, and most now run searchable online portals. You can usually search by address, parcel number, or owner name.

Here's where to look depending on where you live:

• Your county assessor's website (search "[county name] assessor property search")
• Your county auditor's website (some states use auditor instead of assessor)
• Your county appraisal district's website (Texas uses this term; search "[county name] CAD property search")
• State property tax portals (states like New Jersey consolidate records at the state level)

For nyc property tax, the NYC Department of Finance runs a property search tool at nyc.gov/finance where you can pull the assessed value, tax class, and any exemptions on record for any property in the five boroughs ^[2]. For la county property tax, the Los Angeles County Assessor Portal at assessor.lacounty.gov lets you search by APN or address and see the full assessment history ^[10].

Can't find it online? Call the assessor's office. They have to give you your assessment information. Many counties also mail an annual notice of assessment (sometimes called a "valuation notice" or "assessment notice") every year or every reappraisal cycle. That paper notice is the official record, and it starts the clock on your appeal deadline.

For property in santa clara county or contra costa county, the California assessor portals stay well-maintained and show land value and improvement value separately. That split matters if you want to challenge the breakdown instead of just the total.

What determines the assessed value of your property?

The assessor's office picks from three valuation approaches, and sometimes blends all three. Which one applies depends on your property type.

The sales comparison approach (the usual choice for single-family homes) pulls recent sales of comparable properties, adjusts for differences in size, age, condition, and features, and lands on a market value estimate. Assessed value is that estimate times the local ratio.

The cost approach estimates what it would cost to rebuild the structure from scratch, subtracts depreciation, then adds land value. It works fine for newer construction and specialty buildings. It tends to overvalue older homes with functional obsolescence, like a 1960s ranch with one bathroom.

The income approach is for rental and commercial property. It bases value on the net income the property throws off. If an assessor plugs in a cap rate that's too low or an income figure that's too high, the assessed value comes out inflated. That's a common and winnable appeal for landlords.

Mass appraisal complicates all of it. Your assessor isn't walking through your house every year. The algorithm applies neighborhood-level adjustments and statistical models. When the model guesses wrong for your specific property, the error lands on your bill. The International Association of Assessing Officers (IAAO) sets a standard that a jurisdiction's residential assessments should carry a coefficient of dispersion (a measure of uniformity) no higher than 15% ^[4]. Plenty of jurisdictions miss that mark, which means real inequities are baked in.

How do assessment ratios and tax rates connect to your actual bill?

Understand the math and you stop appealing the wrong thing. The bill is a chain, and only some links are worth attacking.

Here's the formula: (Assessed Value minus Exemptions) times Millage Rate equals Tax Bill.

The millage rate gets set by your local governments (city, county, school district, special districts). One mill equals $1 per $1,000 of taxable value. If your taxable value is $300,000 and the combined millage rate is 20 mills, your bill is $6,000.

Now the ratio comes into focus. Say your state uses a 50% ratio and your home's market value is $400,000. Your assessed value should be $200,000. If the assessor pegs your market value at $480,000 instead, your assessed value jumps to $240,000, and at 20 mills you're overpaying $800 a year.

The ratio also shapes how you stack your assessment against your neighbors', a concept called assessment equity. Two houses with the same market value should carry the same assessed value. If yours is higher, that alone is grounds for an appeal in most states, no matter what you think the true market value is.

For a contrast, san mateo county in California runs under Prop 13 with a 100% ratio capped at 2% growth, while collin county in Texas uses 100% of appraised market value with annual reappraisals and no ratio cap. That's why Texas homeowners get slammed with bigger year-to-year swings.

What is the assessed value of a property in NYC specifically?

New York City runs one of the most tangled assessment systems in the country. It earns its own section because so many people search for it and get lost.

NYC sorts properties into four tax classes. Class 1 (one- to three-family residential) is assessed at 6% of market value. Class 2 (larger residential, including co-ops and condos) runs up to 45%. Class 4 (commercial) sits at 45% ^[2].

Then come two more caps. A Class 1 property's assessed value can't rise more than 6% in a single year or 20% over five years, no matter what the market does. So a brownstone bought for $400,000 in 1995 can carry a much lower effective tax rate than an identical brownstone bought in 2022, even if both are worth $2 million today.

You'll find your NYC assessed value at the Department of Finance website (nyc.gov/finance), or on your annual Notice of Property Value (NOPV), which the city mails every January. The NOPV is your launch point for an appeal to the NYC Tax Commission, which you have to file by March 1 for most property classes ^[2].

The system has drawn years of reporting on racial and economic inequity. A 2021 report from the NYC Advisory Commission on Property Tax Reform found that Class 1 properties in lower-income neighborhoods often get assessed at a higher share of their market value than comparable homes in wealthier neighborhoods, a regressive result ^[5].

How accurate are assessed values, and how often are they wrong?

More often than most homeowners guess. Errors aren't rare exceptions. They're a feature of a system that values millions of homes by formula.

A 2021 study by Christopher Berry at the University of Chicago's Harris School found that in many jurisdictions, lower-value homes get assessed at higher rates relative to their market value than higher-value homes, a pattern called "assessment regressivity" ^[6]. The study examined roughly 26 million single-family homes across the country.

The IAAO benchmark for a sound assessment is a median assessment-to-sales ratio between 90% and 110%, meaning the median assessed value should land within 10% of the actual sale price ^[4]. Look at specific counties and many fall outside that band in certain years or for certain property types.

So the odds are decent that your assessment carries some error, especially if:

• Your home hasn't sold recently and the assessor hasn't done an interior inspection
• Your neighborhood ran up fast and the assessor is playing catch-up
• Your neighborhood dropped (common in markets that cooled after 2022 rate hikes) and the assessor hasn't marked it down
• Your property has physical problems the mass appraisal model can't see
• You just bought the place for less than the assessed value

Because errors are common, appeals win a meaningful share of the time when the homeowner brings comparable sales evidence. Reported success rates vary widely by jurisdiction, and the cleanest numbers come from individual state boards of equalization in their annual reports. Nobody publishes a reliable single national figure, so treat any "X% of appeals succeed" claim with suspicion.

How do you challenge an assessed value you think is wrong?

The appeal has a hard deadline, and missing it costs you a full year. Check your state's deadline before you do anything else.

The general sequence:

1. Get your assessment notice and write down the appeal deadline. In most states it's 30 to 90 days from the date on the notice. 2. Pull your property record card from the assessor (most are online now). Check every fact: square footage, bedroom count, lot size, year built, quality grade. Errors here are surprisingly common. 3. Find comparable recent sales. Aim for sales in the last 6 to 12 months, within a mile ideally, similar in size, age, and condition. Your assessor's website often lists sales data, or you can use Zillow, Redfin, or your county's public records. 4. Calculate the implied market value. If three comparable homes sold for an average of $380,000 and your assessed value implies a market value of $440,000, that gap is your evidence. 5. File the appeal form. Most counties use a simple one- or two-page form. You don't need a lawyer or a contingency firm for a residential appeal. 6. Show up for the informal hearing (most jurisdictions offer this first). Bring your comps. Stay specific and factual. 7. If the informal hearing doesn't produce a fair reduction, file for a formal hearing before the board of equalization, assessment appeals board, or appraisal review board (the name changes by state).

Want a structured way to build your evidence file? The TaxFightBack appeal kit walks through this exact process, including how to pick and format comparable sales the way assessors expect to see them.

For williamson county and other fast-growing Texas counties, the appraisal review board (ARB) process carries extra weight because Texas has no assessment ratio cap and values can leap year over year. Texas Tax Code Section 41.41 gives owners the right to protest appraised value, unequal appraisal, or incorrect property data ^[7].

For miami-dade property taxes, the Value Adjustment Board (VAB) handles appeals. Florida Statute 194.011 sets a 25-day filing window from the date the truth-in-millage (TRIM) notice is mailed, usually in August ^[8].

What exemptions can reduce your property's taxable value?

An exemption doesn't touch the assessed value. It cuts the taxable value, which is the number that gets multiplied by the millage rate. That distinction is where a lot of homeowners get tripped up.

The most widely available exemptions:

Homestead exemption. Available in most states for a primary residence. It's either a flat dollar cut (Florida's is $50,000 off assessed value for most homeowners ^[8]) or a percentage. Texas homeowners get a $100,000 homestead exemption off appraised value for school district taxes as of 2023, after Proposition 4 passed ^[7].

Senior exemption. Many jurisdictions add reductions for homeowners over a set age (usually 62 or 65), sometimes with an income cap. These vary a lot by county.

Disability and veteran exemptions. Most states offer some property tax relief for disabled veterans. Texas exempts 100% of a property's value for veterans with a 100% disability rating ^[7].

Agricultural or "greenbelt" exemptions. If your land qualifies for agricultural use, many states assess it on its agricultural income value instead of its development market value. On the suburban fringe, that difference can be enormous.

You have to apply for most exemptions. They don't land on your account by themselves. Check your tax bill or the assessor's website to see which exemptions are already on your record. If you qualify for one that's missing, file the application. Deadlines vary, but March 1 to April 1 for the current tax year is common.

How do states differ in how they calculate assessed value?

The gap between states runs wide enough that a "fair" assessment in one would be an outrage in another. Here's a sample of how the ratios and rules play out ^[9].

State	Assessment ratio (residential)	Reappraisal cycle	Notable caps
California	100% of purchase price	Annual, but capped (Prop 13)	2% annual growth cap until sale
New York (NYC Class 1)	6% of market value	Annual	6%/yr, 20% over 5 years
Texas	100% of market value	Annual	10%/yr cap on homestead taxable value
Michigan	50% of market value	Annual	5% or inflation cap on taxable value
Florida	100% of market value (just value)	Annual	Save Our Homes: 3%/yr or CPI cap
Illinois (Cook County residential)	10% of market value	Triennial	None on assessed, but equalization factor applied
Massachusetts	100% of full cash value	Annual (triennial inspections)	None on assessed value

So you can't compare assessed values across state lines. A $150,000 assessed value in California and a $150,000 assessed value in Texas say completely different things about what the property is actually worth.

For deeper jurisdiction guides, see our coverage of hennepin county property tax and detroit property taxes, which show how Michigan's 50% ratio and taxable value cap land on real bills in real counties.

What should you do right now if your assessment just arrived?

Don't toss it. Your assessment notice is a piece of financial information and the start of a legal clock at the same time.

First, write down the appeal deadline. It's usually printed on the notice. If it isn't, call the assessor's office today.

Second, pull your property record card and verify every factual item. Square footage errors happen all the time. A house recorded as 2,200 square feet that's really 1,900 is getting taxed on 300 phantom feet. Fixing the factual record is often the fastest, easiest win there is.

Third, estimate your market value honestly. Recent comparable sales are the best evidence. If you bought the house in the last two years and paid less than the market value the assessment implies, that's powerful.

Fourth, check your exemptions. Is your homestead exemption on file? Any senior or disability exemption you qualify for and haven't claimed?

Still looks high after all that? File the appeal. It costs nothing to file in most jurisdictions, and losing an appeal changes nothing. You just pay what you were already going to pay.

The TaxFightBack appeal kit is built for this exact moment. It gives you the comparable sales template, the property record card checklist, and the evidence packet format that makes informal hearings go fast. You keep 100% of what you save.

For owners who handle online tax payment for property, appealing before you pay can sometimes let you pay under protest and get a refund if the appeal wins. The rules on paying under protest change by state, so check yours.

Frequently asked questions

What is the assessed value of a property in simple terms?

Assessed value is the dollar figure your local government uses to calculate your property tax bill. It's usually based on market value, often multiplied by a percentage called the assessment ratio that varies by state. It isn't necessarily what your home would sell for. A house worth $500,000 on the market might carry an assessed value of $250,000 in a state with a 50% ratio, or $500,000 in a state that assesses at full market value.

How do I find the assessed value of my property online?

Go to your county assessor's website and search by address or parcel number. Most counties run free online portals. In Texas, search your county appraisal district's website. In NYC, use the Department of Finance property search at nyc.gov/finance. If there's no portal, call the assessor's office; they have to give you this information. Your annual assessment notice also states the number.

Is assessed value the same as market value?

No. Market value is what buyers and sellers agree a property is worth. Assessed value is what the government decides to tax. Many states set assessed value at a percentage of market value (50%, 6%, 100%, and so on) using an assessment ratio. Even in states aiming for 100% of market value, the assessor's estimate can be wrong because it comes from a mass appraisal model, not an individual sale.

Can I appeal my property's assessed value myself without hiring anyone?

Yes. Most residential assessment appeals get filed and won by homeowners with no attorney or contingency firm. You need your assessment notice, your property record card (from the assessor), and two to four recent sales of comparable homes nearby. The filing forms are free. Contingency firms typically keep 25% to 50% of your first-year savings. Doing it yourself keeps all of it.

How often does assessed value change?

It depends on your state's reappraisal cycle. California only reassesses when a property sells. Many states reassess annually. Others do it every two, three, or four years. Within those cycles, states like Michigan and Florida cap how fast assessed or taxable value can rise, so your annual increase may be limited even when the market jumps sharply.

What is the difference between assessed value and taxable value?

Assessed value is what the assessor determines. Taxable value is assessed value minus any exemptions you qualify for, like a homestead exemption. Your bill runs off taxable value, not assessed value. In states with growth caps, taxable value can also sit below assessed value because the cap limits how fast taxable value can climb each year, even when assessed value rises faster.

Why is my assessed value lower than my home's market value?

Most likely your state applies an assessment ratio below 100%, or a growth cap (like California's Prop 13 or Florida's Save Our Homes) has kept your assessed value from keeping pace with rising prices. This isn't a problem unless you're selling. If you plan to stay, a low assessed value relative to market value just means a lower tax bill.

Why is my assessed value higher than what I paid for the house?

This can happen if you bought during a price dip and area values have since risen, or if the assessor uses a different method than the sale price. In some states, a recent sale price is binding evidence of market value. In others, it's one data point. If your assessed value implies a market value above what you paid, your purchase price is your strongest evidence in an appeal.

How is NYC property assessed value calculated?

NYC uses four tax classes with different ratios. Class 1 (one- to three-family homes) is assessed at 6% of market value, with increases capped at 6% per year and 20% over five years. Class 4 (commercial) is assessed at 45%. The Department of Finance mails a Notice of Property Value every January. You can look up any property at nyc.gov/finance. The appeal deadline for most classes is March 1.

What happens to assessed value when I sell my home?

In purchase-price states like California, the sale triggers a full reassessment to the sale price. That's why California buyers often see a big jump in the tax bill after closing. In states with annual reappraisals (most of them), the sale may not change assessed value right away, but the assessor can use it as a data point in the next cycle.

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

Usually yes, but the millage rate matters too. A jurisdiction could lower its millage rate when assessed values rise across the board, keeping bills flat. That does happen. In practice, many jurisdictions don't cut rates enough to offset rising assessments, so homeowners in hot markets often watch their bills climb with no change in local tax policy.

What is a good assessment ratio and where can I find mine?

The International Association of Assessing Officers considers a median assessment-to-sales ratio between 90% and 110% accurate. Your state's ratio is usually set by statute. Your state department of revenue or taxation website lists the required assessment ratio for each property class. Some counties publish an equalization study each year showing the actual median ratio they hit.

How long does an assessment appeal take?

An informal hearing with the assessor's office usually happens within 30 to 90 days of filing and can sometimes be settled by phone or mailed-in evidence. A formal hearing before an appeals board typically runs 60 to 180 days. In high-volume places like Cook County, Illinois or NYC, backlogs can push a formal hearing out 12 to 18 months. Most homeowners settle at the informal stage.

Do I still owe property tax if I'm appealing my assessed value?

Yes, in most states. You generally have to pay your bill by the due date even while appealing, or you risk penalties. Some states let you pay under protest and get a refund if the appeal wins. Check your state's rules before assuming payment is optional during an appeal. Missing a payment deadline while waiting on an outcome is a costly mistake.

Sources

1. California State Board of Equalization, Proposition 13 Overview: Under Proposition 13, California residential properties are assessed at 100% of their most recent purchase price with a 2% annual increase cap.
2. NYC Department of Finance, Property Tax Rates and Classes: NYC Class 1 properties are assessed at 6% of market value; Class 4 commercial at 45%; Class 1 annual increase capped at 6%/year and 20% over five years; NOPV mailed in January; Tax Commission appeal deadline March 1.
3. Michigan Department of Treasury, Property Tax Taxable Value: Michigan's taxable value cannot increase more than 5% or the rate of inflation (whichever is less) in any year until the property is sold.
4. International Association of Assessing Officers (IAAO), Standard on Ratio Studies: IAAO standard requires a median assessment-to-sales ratio between 90% and 110% and a coefficient of dispersion no higher than 15% for single-family residential properties.
5. NYC Advisory Commission on Property Tax Reform, Final Report 2021: The commission found that Class 1 properties in lower-income neighborhoods are often assessed at a higher percentage of market value than comparable properties in wealthier neighborhoods.
6. University of Chicago Harris School, The Property Tax Fairness study (Christopher Berry, 2021): Analysis of roughly 26 million single-family homes found that lower-value homes are systematically assessed at higher rates relative to market value than higher-value homes in many U.S. jurisdictions.
7. Texas Comptroller of Public Accounts, Property Tax Code Section 41.41: Texas Tax Code Section 41.41 grants property owners the right to protest appraised value, unequal appraisal, or incorrect property data; 2023 Proposition 4 increased the homestead exemption for school district taxes to $100,000; 100% disabled veterans are fully exempt.
8. Florida Department of Revenue, Property Tax Oversight, TRIM Notice: Florida Statute 194.011 sets a 25-day filing deadline from the TRIM notice mailing for Value Adjustment Board appeals; Florida's homestead exemption is $50,000 off assessed value.
9. Lincoln Institute of Land Policy, 50-State Property Tax Comparison Study: Assessment ratios, reappraisal cycles, and caps vary substantially by state; Lincoln Institute annual 50-state study documents effective tax rates and assessment practices across all states.
10. Los Angeles County Assessor, Property Search Portal: LA County Assessor portal allows search by APN or address and displays full assessment history including land and improvement value breakdown.
11. Illinois Department of Revenue, Property Tax Statistics: Cook County residential properties are assessed at 10% of market value with a triennial reassessment schedule; an equalization factor is applied by the state.