Appraised value versus assessed value: what's the difference and why it matters for your tax bill

Last updated 2026-07-09

What is appraised value?

Appraised value is the county assessor's estimate of what your property would sell for between a willing buyer and a willing seller, with no pressure on either side. It goes by several names depending on your state: fair market value, full cash value, true cash value, or just plain market value. They all mean the same thing.

The assessor gets to this number three ways. Recent sales of comparable homes. The income a rental property throws off. Or the cost to rebuild the structure from scratch. Residential properties almost always get the sales comparison approach, meaning the assessor finds homes that sold near yours and adjusts for differences in size, age, condition, and location. ^[1]

Your mortgage lender's appraisal and the county's appraised value are two different animals. Two different people, two different reasons. The lender hires a licensed appraiser to protect the loan, and that person walks through your house. The county assessor mass-appraises every parcel at once, usually with software, usually without ever setting foot inside. That gap in method is exactly why county appraised values are so often wrong, and so often worth challenging.

What is assessed value?

Assessed value is the dollar figure the county actually multiplies the tax rate against. In a lot of states it is not the full appraised value. State legislatures set an assessment ratio, sometimes called the assessment level or assessment percentage, that decides what slice of appraised value gets taxed. ^[2]

The formula is simple: Assessed Value = Appraised Value × Assessment Ratio.

Say your home's appraised value is $400,000 and your state uses a 40% ratio. Your assessed value is $160,000. A 2.5% tax rate applies to the $160,000, not the $400,000, so your annual bill is $4,000 instead of $10,000. The ratio quietly cuts your taxable base by more than half.

This ratio swings hard from state to state. California's Proposition 13 effectively locks assessed value growth at 2% a year no matter what the market does, so a home bought in 1990 can carry an assessed value far below its current price. ^[3] At the other end, Delaware and New Hampshire aim for a 100% ratio, meaning assessed value and appraised value are supposed to match. No mass appraisal system hits exactly 100% in practice, but the intent tells you how to read your notice.

How do appraised value and assessed value compare across states?

Assessment ratios run from 6% to 100% depending on the state, and actual ratios drift from the statutory target because reassessments land on different cycles. Before you compare your numbers to anyone else's, you have to know your state's ratio.

The table below shows the statutory assessment ratio and any state-level cap for a handful of states.

State	Statutory assessment ratio	Reassessment cycle	Notes
California	~25% (Prop 13 effect)	Annual, value capped at 2%/yr growth	Effective ratio far below 100% for long-held homes [3]
Texas	100%	Annual	Homestead value increase capped at 10%/yr [4]
Illinois (Cook Co.)	10% (residential)	Triennial	Separate appeal tracks for assessor and BOR [5]
Georgia	40%	Annual	Fair market value x 40% = assessed value [6]
New York	Varies by municipality	Varies	NYC uses 6% for Class 1; upstate varies widely [7]
Arizona	10% (residential)	Annual	Limited property value also constrains increases [8]
Florida	100% (Just Value)	Annual	Save Our Homes cap limits assessed increases to 3%/yr or CPI [9]

Here's the practical lesson. A $500,000 appraised value sitting next to a $200,000 assessed value is completely normal in Georgia, because Georgia taxes 40% of market value. ^[6] The same pairing in Texas would mean something is broken, because Texas taxes 100%. Read your notice against your own state's ratio, never against a neighbor in a different state.

What is market value and how does it differ from appraised value?

For property tax purposes, appraised value and market value are the same thing. The International Association of Assessing Officers (IAAO), which writes the professional standards for mass appraisal, defines market value as "the most probable price a property should bring in a competitive and open market." ^[1] Assessors are told to estimate that price and call it appraised value.

The confusion starts because "appraised value" sometimes means a private appraisal ordered by a homeowner or lender, while "market value" is the term the assessor's office prints. They measure the same concept. The private appraisal is usually the more reliable of the two, because it's a single-property, interior-inspected estimate by a licensed professional. The county number is a statistical model run across tens of thousands of parcels at once.

Mass appraisals get less accurate for odd properties, for homes in thin markets with few sales, and for homes at the very top or bottom of their neighborhood's price range. A 2021 analysis in Cityscape, a HUD research journal, found that assessment ratios for lower-value homes exceeded those for higher-value homes in nearly every jurisdiction studied, which means cheaper homes tend to be overassessed relative to market value. ^[10] If your home sits below the median for your street, that finding is worth reading twice.

How does the assessment ratio affect your actual tax bill?

Your bill is Assessed Value × Effective Tax Rate = Annual Tax. Assessed value is the number that matters, because that's what the rate multiplies against. The ratio decides how much each dollar of appraisal error actually costs you.

The effective tax rate already bundles every local levy stacked on top of each other: the school district, the municipality, the county, and any special districts.

Run the numbers and it gets concrete fast. If your appraised value is wrong by 10% in a state with a 100% ratio and a 1.5% effective rate, that error on a $400,000 home costs you $600 a year. Same error, same rate, but a 40% ratio state, and it costs you $240 a year. Nothing changed except the ratio.

Exemptions come off the assessed value after the ratio is applied. A $25,000 homestead exemption cuts your taxable assessed value by $25,000, not your appraised value by $25,000. In a 100% ratio state the two are the same. In a 40% ratio state, you'd need a $62,500 error in appraised value to match the benefit of a $25,000 assessed value exemption. That math should decide where you spend your energy: fighting the appraisal, or making sure you've claimed every exemption you qualify for.

What should you look at first: appraised value or assessed value when checking for overassessment?

Start with the appraised value on your notice. That's the assessor's guess at what your home is worth on the market, and it's the number you almost always appeal. If it looks high next to what comparable homes actually sold for, you have grounds.

Assessed value sits downstream. Get the appraisal right and the assessed value falls into place, because the ratio is fixed by statute. Your argument at a review board is about the market estimate, not the arithmetic of the ratio.

There are exceptions. Some counties slap the wrong classification on a property, charging a commercial ratio on a residential home, or botch the ratio itself. Cook County, Illinois has a documented history of classification errors that pushed residential properties into higher commercial rates. ^[5] If your ratio looks off, pull the county assessor's published classification schedule and hold it against your notice.

Then check your property's description. Assessors carry wrong square footage, bedroom counts, and lot sizes from records that never got updated. A home listed as 2,400 square feet when it's really 1,900 is carrying an inflated appraisal with no basis in the market at all. That's one of the easiest appeals going. No comps required, just a tape measure and the assessor's own data card.

How do you find your home's appraised value and assessed value?

Your county mails an assessment notice once a year, or once per reassessment cycle, and it shows both numbers. Missed it? Every county with a working assessor's website lets you look up your parcel by address. Search "[your county] property search" and you'll land on a public portal with your appraisal, assessed value, and tax history.

The notice usually shows a line for appraised value or fair market value, a line for the assessment ratio or level, and the resulting assessed value. Some spell out the ratio. Others just print the two dollar amounts and leave you to divide one by the other.

For county-specific lookup tools, we have guides for several major counties: Los Angeles County property tax, Cook County tax assessor tax bill, Maricopa property tax, and San Diego property tax.

Want to cross-check the county against what buyers are really paying? Pull recent sales from your county recorder's website, Zillow's sold listings, or Redfin. Filter to homes that closed in the last 6 to 12 months, within a half mile, and within 20% of your square footage. Those are your comparables. They're the same evidence you'd hand a review board.

Can you appeal if the assessed value is lower than the appraised value?

Yes, and in most states the number you actually appeal is the appraised (market) value on your notice, not the assessed value. Win the appraisal and the assessed value drops on its own, because the county reapplies the ratio to the new, lower figure.

In states with a uniform ratio by property class, the only winning move is proving the appraised value sits above real market value. You can't argue the ratio itself is wrong unless you can show the assessor applied the wrong classification to your parcel.

A few states allow a different challenge, called a ratio appeal or equalization appeal. If the assessor is consistently appraising your neighborhood at 110% of market value while the statutory target is 100%, some states let you argue your assessed value should drop to match the correct ratio, even when your individual appraisal is accurate. The IAAO's Standard on Ratio Studies lays out the methodology assessors are supposed to use to check their own ratios. ^[1]

For most DIY appeals the path is plainer. Pull three to five comparable sales from the 12 months before the assessment date, show they point to a lower market value than the county claims, and put that evidence in front of the review board. That approach works in every state.

What's the difference between an appraised value appeal and an exemption claim?

They're two separate levers for cutting your tax bill, and people mix them up constantly. Use both if you can.

An appraised value appeal attacks whether the assessor's market estimate is accurate. The argument runs: comparable homes sold for less, so my appraised value should be lower, so my assessed value and my bill should drop.

An exemption claim never touches the appraised value. It cuts the assessed value directly, by a fixed dollar amount or a percentage. Homestead, senior citizen, disability, veterans, these all come off the assessed value after the ratio has already been applied. Some are dollars off. Some are a percentage off.

Go after both if you qualify for exemptions and think the appraised value is too high. They aren't mutually exclusive, and skipping an exemption while you obsess over the appeal is a common, expensive miss. In Georgia, a basic homestead exemption knocks $2,000 off the assessed value for state taxes, but many counties stack extra local exemptions on top, so the total reduction often runs $10,000 or more. ^[6]

For Georgia counties, check the guides for Gwinnett County tax assessor, Cherokee County tax assessor, and Coweta County tax assessor for local exemption details.

How do assessment caps and phase-ins change the relationship between appraised and assessed value?

Many states throw a third number into the mix: taxable value, sometimes called limited assessed value. It's the assessed value after a statutory cap slows how fast it can climb in a hot market. The cap protects you from a runaway bill even when the market runs away.

Florida's Save Our Homes cap limits the annual rise in assessed value for homesteaded properties to the lesser of 3% or the change in the Consumer Price Index. ^[9] So if your appraised (just) value jumps 15% in a year, your assessed value still only moves 3%. The gap between the two is the Save Our Homes benefit, and it vanishes when you sell.

Texas caps year-over-year growth in homestead assessed value at 10%, no matter what the market does. ^[4] California's Proposition 13 holds annual assessed value increases to 2% and resets to market value only when the property changes hands or gets major new construction. ^[3]

These caps are a gift to longtime owners and a shock to new buyers. Buy a California home from someone who owned it 30 years, and your assessed value resets to your purchase price, which may tower over the seller's old assessed value. That's not an error. That's the statute working as written. Figure out whether your state has a cap, and whether it touches your property, before you decide you have a real appeal.

Should you hire an appraiser or do the appeal yourself?

For most single-family appeals, you don't need a licensed appraiser. Review boards want comparable sales, and you can pull that data yourself from public records, Zillow, Redfin, or your county recorder. Homeowners represent themselves at these hearings every single day, and the board expects it.

A contingency firm sounds easy. They take a cut of the tax savings, usually 25% to 50% of the first year's reduction. On $1,000 of annual savings, that's $250 to $500 gone right away, often for two or three years running while the contingency clause holds. You keep more doing it yourself, even if your filing isn't polished.

A licensed appraisal runs roughly $300 to $600 for a residential property, based on ranges reported by Angi. ^[11] Order one if your property is unusual (waterfront, acreage, historic designation), if the dollars at stake are large, or if the county is fighting your comparable selection hard. For a standard suburban home where the comps clearly support a lower value, keep the fee in your pocket.

Want a structured process for gathering comps, writing the appeal letter, and presenting at the hearing? The TaxFightBack DIY appeal kit walks through each step with state-specific deadlines and form templates, so you keep 100% of whatever reduction you win.

For appeal procedures in specific counties, the guides for Bexar County tax assessor, Lake County property tax, and Madison County tax assessor cover local filing rules.

What are the key deadlines for appealing your appraised value?

Miss the deadline and you're locked out for a full year. Deadlines vary by state and sometimes by county, so treat the date on your notice as a countdown clock.

Texas owners have until May 15, or 30 days after the appraisal notice is mailed, whichever is later, to file a protest with the Appraisal Review Board. ^[4] Georgia owners generally get 45 days from the date on the assessment notice. ^[6] Cook County, Illinois runs a triennial system, so your township only gets reassessed every three years, and the appeal window is roughly 30 days from when the assessor publishes the township's reassessment roll. ^[5]

California's regular filing period in most counties runs July 2 through November 30 for the annual Assessment Appeals Board hearing. ^[3] Florida's deadline to petition the Value Adjustment Board is 25 days after the TRIM (Truth in Millage) notice is mailed, which usually happens in August. ^[9]

Do this the day your notice arrives: set a calendar alert, then look up your state's statutory deadline right then. Assessor websites almost always post the current year's appeal deadline on the homepage. Don't trust your memory. The IAAO publishes general reference material on appeal windows, but your county assessor's site is the authoritative source for your exact date. ^[1]

Frequently asked questions

Is appraised value the same as market value?

Yes, for property tax purposes these terms mean the same thing. Your county assessor's appraised value is their estimate of what your home would sell for on the open market. Different states use different words: Texas says "appraised value," California says "full cash value," Florida says "just value," but they all target one concept. A private lender appraisal and the county's estimate measure the same thing using different methods, so they often reach different numbers.

Why is my assessed value lower than my appraised value?

Most states apply an assessment ratio below 100%, so assessed value is intentionally a fraction of appraised value. Georgia uses 40%, Cook County Illinois uses 10% for residential, and Arizona uses 10% for residential. Some states also cap annual increases in assessed value, which widens the gap in hot markets. Check your state's statutory ratio to confirm the difference is correct rather than an error.

Which value do I appeal, appraised or assessed?

In nearly every state, you appeal the appraised (market) value. Win, and the assessed value drops automatically, because it's calculated from the appraised value using a fixed ratio. Your evidence is comparable sales showing the market value should be lower. The one exception: if you believe the wrong ratio or property classification was applied, you challenge the classification instead of the market estimate.

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

Not automatically, thanks to caps and phase-ins. Florida, Texas, and California limit how fast assessed value can rise in a year even when appraised value jumps. So your appraised value might climb 15% while your assessed value, and your bill, rises only 3%. That cap resets to full market value when you sell, which is why buyers sometimes see a big first-year tax jump.

Can I use a Zillow estimate to dispute my appraised value?

Not directly. The Zestimate is an automated algorithm, not a licensed opinion of value, so most appeal boards won't accept it as evidence. What you can use is the sales data underneath it: actual closed transactions from the MLS or public records. Pull the comparable sales Zillow displays and present those sale prices. The sales data is real. The Zestimate itself is not.

How often do counties reassess property values?

It varies by state and sometimes by county. Texas, Georgia, and Florida reassess annually. Cook County Illinois runs a triennial cycle, reassessing residential properties once every three years by township. Some jurisdictions only reassess when they run a countywide revaluation, which might come every four to six years. Your assessment notice shows the appraisal year; check your county assessor's site for the reassessment schedule.

What is an equalization factor and how does it affect assessed value?

An equalization factor is a multiplier the state applies to county assessed values to pull them toward a uniform assessment level. Illinois publishes a county equalization factor each year. If a county's assessed values run below the statutory level, the state multiplies them upward. This factor lands after the assessor sets your value, so the assessed value on your final tax bill can differ from the number on the assessor's notice.

Does my assessed value affect my homeowner's insurance?

No. Homeowner's insurance is based on replacement cost, meaning what it would cost to rebuild the structure, not market value or assessed value. The insurer doesn't care what your home would sell for; they care what it costs to reconstruct after a total loss. These numbers can diverge a lot, especially for older homes or in places where land value is a big share of market value.

What happens to the assessed value when I buy a house?

In states without an acquisition-value system, nothing automatic happens: your assessed value follows the regular reassessment cycle. In California, a sale triggers reassessment to the purchase price under Proposition 13, which becomes the new base for the 2%-per-year cap. In some Florida counties, buying resets the Save Our Homes benefit to zero. Check your state's change-of-ownership rules before closing so the first tax bill doesn't blindside you.

Can the assessor raise my appraised value after I file an appeal?

In most states, no, the assessor cannot raise your value because you appealed. But some states let the appeal board increase a value if the evidence reveals the original estimate was actually too low. Texas is one: the Appraisal Review Board can raise values above the original assessment. It's rare in practice, and usually happens only when a homeowner presents evidence that accidentally reveals a higher value. Check your state's statute before filing.

How do I know if my appraised value is accurate?

Pull three to five sales of comparable homes that closed within 12 months before your assessment date, within a reasonable distance, and similar in size and age. Calculate the price per square foot for each, then multiply by your home's square footage. If that figure sits meaningfully below the assessor's appraised value, say more than 5% to 10%, you have a case. Also check the assessor's data card for wrong square footage, bedroom count, or lot size.

What is the difference between assessed value and taxable value?

Assessed value is what you get when you apply the assessment ratio to the appraised value. Taxable value is what you actually get taxed on after exemptions and any statutory caps come off the assessed value. In many states these match if you have no exemptions. In Florida the hierarchy runs: just (market) value, then assessed value after the Save Our Homes cap, then taxable value after exemptions. Your tax rate applies to the taxable value, not the assessed value.

My mortgage lender's appraisal is lower than the county's appraised value. Can I use it in an appeal?

Yes, and it can be strong evidence. A licensed appraisal by a certified appraiser, done with an interior inspection and a full written report, carries more weight than a mass-appraisal estimate. Bring the whole report to your hearing, more than the summary page. Watch the effective date: it should sit as close as possible to the county's valuation date. A lender appraisal from six months before the assessment date is strong; one from two years earlier is not.

Is assessed value public record?

Yes, in all 50 states. Property assessment records are public, which is why you can look up your neighbor's assessed value on the county assessor's website. The transparency is on purpose: it lets owners verify their home is assessed consistently with comparable properties. Use it to check whether similar homes nearby carry lower assessed values, which is relevant evidence for an equalization or uniformity argument at appeal.

Sources

1. International Association of Assessing Officers (IAAO), Standard on Mass Appraisal of Real Property: IAAO defines market value as the most probable price a property should bring in a competitive and open market, and sets professional standards for mass appraisal methodology and ratio studies.
2. Lincoln Institute of Land Policy, Significant Features of the Property Tax: Assessment ratios vary by state and property class, determining what fraction of appraised value is subject to tax.
3. California State Board of Equalization, Proposition 13 Overview: California's Proposition 13 limits annual growth in assessed value to 2% and resets to market value upon change of ownership or new construction.
4. Texas Comptroller of Public Accounts, Property Tax Basics: Texas requires properties to be appraised at 100% of market value annually and caps homestead assessed value increases at 10% per year; protest deadline is May 15 or 30 days after notice mailing.
5. Cook County Assessor's Office, Assessment Overview: Cook County Illinois uses a 10% assessment ratio for residential properties and a triennial reassessment cycle by township.
6. Georgia Department of Revenue, Property Tax Guide: Georgia assessors are required to appraise property at 100% of fair market value, with a 40% assessment ratio applied, and property owners have 45 days from the notice date to appeal.
7. New York City Department of Finance, Property Tax Classes: New York City Class 1 residential properties carry a 6% assessment ratio; assessment ratios vary widely across upstate New York municipalities.
8. Arizona Department of Revenue, Property Tax Overview: Arizona applies a 10% assessment ratio to residential properties and uses a Limited Property Value mechanism to constrain year-over-year assessed value increases.
9. Florida Department of Revenue, Property Tax Overview: Florida targets 100% just value for appraisal but the Save Our Homes cap limits annual assessed value increases for homesteaded properties to the lesser of 3% or the CPI change; Value Adjustment Board petition deadline is 25 days after the TRIM notice.
10. Cityscape (HUD), Reassessing the Regressive Property Tax, Vol. 23 No. 3 (2021): A 2021 HUD Cityscape analysis found that assessment ratios for lower-value homes exceeded those for higher-value homes in nearly every jurisdiction studied, indicating systematic overassessment of lower-value properties.
11. Angi (formerly HomeAdvisor), Home Appraisal Cost Guide: Licensed residential appraisals typically cost $300 to $600 for a standard single-family home, varying by property size and location.