Assessed Value vs Market Value: A Guide for Investors

Assessed value vs market value comes down to purpose: assessed value is the number a county uses to calculate property tax, while market value is what a willing buyer would actually pay today. For investors and wholesalers, the gap between the two can run into six figures, so the assessed value on a tax card should never stand in for market value, ARV, or your offer price.

2%Max yearly assessment increase under Prop 13 (CA Board of Equalization)

2.7%Florida Save Our Homes cap for 2026 (FL Dept. of Revenue)

10%Cook County residential assessment level (Cook County Assessor)

Most guides on this topic are written for homeowners. This one is for people buying, assigning and renting property: how assessors set the number, why state caps pull it away from reality, how to mine assessment data for leads, and how to estimate the tax bill your end buyer will pay after closing.

Four numbers, four jobs: assessed, market, appraised and taxable value

Each “value” answers a different question for a different person.

Market value is the likely sale price between a willing buyer and seller, neither under pressure, in an arm’s-length transaction.
Assessor’s market value (called “just value” in Florida, “true cash value” in Michigan, “fair cash value” in Illinois, “appraised” or “market” value by Texas appraisal districts) is the assessor’s mass-appraisal estimate, usually pegged to a fixed date such as January 1.
Assessed value is the figure after the state’s assessment ratio and any caps are applied.
Taxable value is what remains after exemptions (homestead, senior, veteran and so on) are subtracted. The tax rate is applied to this number.

Outside the tax system you will also see a lender’s appraised value, a licensed appraiser’s opinion for one specific property on one date; an AVM such as a Zestimate, which is an algorithm working from public records and listing data with no interior inspection; and a broker price opinion (BPO), an agent’s informal value estimate often ordered by lenders on short sales and REOs. None of these is the assessed value, and only comps tell you what a cash buyer or retail buyer will pay.

The assessment formula behind every tax card

The mechanics look the same nearly everywhere, even though the inputs vary by state:

The assessor estimates market value for every parcel using mass appraisal: sales of similar properties, cost tables for improvements, and income data for rentals and commercial buildings.
An assessment ratio converts that estimate to assessed value. Illinois assesses most property at 33 1/3% of fair market value; Michigan’s state equalized value is 50% of true cash value; Texas appraises at full market value.
A cap, if the state has one, limits how much the assessed or taxable value may rise each year, regardless of what the market did.
Exemptions reduce the value that is taxed.
The combined tax rate (millage) from the county, city, school district and special districts is applied to taxable value.

Mass appraisal is imprecise. The International Association of Assessing Officers’ Standard on Ratio Studies treats an overall appraisal level between 0.90 and 1.10 as acceptable, and allows a coefficient of dispersion of up to 15.0 for single-family homes in older, mixed neighborhoods. Put plainly, a county can be doing its job well while individual houses sit well above or below their real price.

Why assessed value vs market value gaps get so wide: state caps and resets

Several large states cap annual assessment growth, so a long-held property can be assessed at a fraction of what it would sell for. Most of those caps end when the property sells, which is exactly when your buyer steps in.

State	How value is set	Annual limit	What happens at sale
California (Prop 13)	Base year value set at change in ownership or new construction; sale price presumed to be market value; tax rate 1% plus voter-approved bonds	No more than 2% per year (CPI or 2%, whichever is less)	Reassessed to market value; supplemental tax bill issued for the rest of the fiscal year
Florida	Just value (market value)	Homestead: 3% or CPI, whichever is lower (2.7% for 2026). Non-homestead: 10%, but not for school levies	Reset to just value January 1 of the year after the change of ownership
Texas	Appraised at 100% of market value by county appraisal districts	Homestead: 10%. Non-homestead real property valued at or under a threshold ($5 million for 2024, CPI-adjusted to $5.16 million for 2025): 20% “circuit breaker,” statute set to expire December 31, 2026	Homestead cap ends when the owner no longer qualifies; the circuit breaker ends the year after the owner sells
Illinois	Most property at 33 1/3% of fair market value; Cook County uses classes, with residential at 10%	No sale-based cap like the others here; most township counties outside Cook run a general reassessment every fourth year	No sale-triggered reset; recorded sales feed the assessor’s market data
Michigan (Proposal A)	State equalized value = 50% of true cash value; tax is on taxable value	Taxable value rises by the lesser of 5% or inflation (2026 multiplier: 1.027)	Taxable value “uncaps” to SEV the year after a transfer

Sources for the table: the California Board of Equalization’s Proposition 13 overview and supplemental assessment page; the Florida Department of Revenue’s Save Our Homes cap history and Fla. Stat. 193.1554; Texas Tax Code Sections 23.23 and 23.231; the Illinois Department of Revenue and 35 ILCS 200/9-215 and the Cook County Assessor; and local assessor guides to Michigan’s Proposal A citing MCL 211.27a. Caps and thresholds change, so confirm the current year with the county before you rely on them. Texas in particular may extend, change or let the circuit breaker lapse after 2026.

States without caps still lag the market. Many counties reassess on multi-year cycles, and a January 1 valuation date means the tax card you read in the fall of a hot year is already stale.

How investors actually use assessment data

Assessor records are free and public, which makes them great raw material for marketing, as long as you use them to find owners, not to price houses.

Building lead lists from the assessor’s file

The assessor’s roll tells you owner name, mailing address, property use, year built, square footage, last sale date and price, and exemption status. That is enough to build several classic lists: absentee owners (mailing address differs from property address), long-tenure owners (last sale 15 or more years ago), and non-owner-occupied properties that lost or never had a homestead exemption.

Reading the assessed-to-market gap as an equity signal

In capped states, a very low assessed value relative to nearby sales usually means the owner has held the property a long time. Long tenure often, though not always, means a small or paid-off mortgage. Treat it as a hint, then confirm with recorded mortgages or a title search. Some long-time owners have refinanced or taken out reverse mortgages, and the assessor’s file will not show that.

Tax delinquency and list stacking

The tax collector’s delinquency list is one of the strongest motivation signals, especially when paired with other distress such as a notice of default. Our guide to pre-foreclosure and tax-delinquent leads walks through pulling those records. The real lift comes from list stacking: an absentee owner who is behind on taxes, holds a code violation and has owned for 20 years is a far better call than any one of those lists on its own.

Your buyer’s real tax bill after the sale

The seller’s current tax bill reflects the seller’s capped value and the seller’s exemptions. Your buyer will usually get neither. To estimate what the buyer will pay:

Check whether the state resets on sale (see the table) and when. California sends a prorated supplemental bill soon after the change in ownership; Florida and Michigan reset in the next tax year.
Remove exemptions the buyer will not qualify for. An investor buying a rental will not get a homestead exemption.
Estimate the new assessed value from the purchase price (or the assessor’s likely market value) times the local assessment ratio.
Multiply by the current total millage from the county tax collector, not an online average.
Run the buyer’s numbers with that figure and show your math on the deal sheet.

Worked example: a rental before and after reassessment (hypothetical)

All figures below are hypothetical and rounded. A single-family rental in a county that reassesses on sale has been owned for 18 years. The tax card shows an assessed value of $110,000 and taxes of $2,200 a year (a 2.0% combined rate). A landlord buyer pays $195,000 with 25% down ($48,750) plus $5,000 in closing costs, and finances $146,250 at 7% over 30 years ($973 a month principal and interest). Market rent is $1,900 a month. After the sale, the assessor puts the house at $190,000, so taxes rise to $3,800.

Line item (annual, hypothetical)	Using seller’s tax bill	After reassessment
Gross rent	$22,800	$22,800
Vacancy (6%)	-$1,368	-$1,368
Effective gross income	$21,432	$21,432
Insurance, maintenance, management, other	-$5,539	-$5,539
Property tax	-$2,200	-$3,800
Net operating income	$13,693	$12,093
Cap rate on $195,000	7.0%	6.2%
Debt service	-$11,676	-$11,676
Annual cash flow	$2,017 ($168/mo)	$417 ($35/mo)
Cash-on-cash return on $53,750	3.8%	0.8%

One line changed, and the deal went from thin to barely breathing. The $1,600 drop in net operating income is worth about $22,900 of value at a 7% cap rate. A buyer who discovers this after closing will not buy from you again. A buyer who sees it on your deal sheet will either adjust the price or trust you more. Run your own scenarios in the cash-on-cash return calculator with the post-sale tax figure, not the seller’s.

Price from comps, never from the tax card

Assessed value is backward-looking, capped, ratio-adjusted, and based on an exterior record that may not reflect a new roof, a gutted kitchen or a cracked foundation. ARV is forward-looking: what this house will sell for after repairs, based on recent sales of similar renovated homes nearby.

Your pricing process should start with pulling real estate comps: closed sales within the last three to six months, similar size, age, bed and bath count, and condition, ideally in the same subdivision. From there, calculate ARV by adjusting for differences, subtract a realistic repair budget, and work back to an offer. The ARV calculator and MAO calculator handle the arithmetic. Assessment data still helps here as a cross-check: if the tax card shows 1,100 square feet and the listing says 1,600, find out whether there is an unpermitted addition before you count that space in your ARV.

When a seller’s assessment is too high: the appeal process

Sometimes the gap runs the other way, especially on distressed property the assessor valued as if it were in average condition. Every state has an appeal process, and the deadlines are short:

Texas: protest to the appraisal review board by May 15 or 30 days after the appraisal notice is mailed, whichever is later. After the ARB, owners can go to district court, binding arbitration (for homesteads, or property appraised at $5 million or less), or, for values over $1 million, the State Office of Administrative Hearings, according to the Texas Comptroller.
Florida: petition the value adjustment board within 25 days after the TRIM notice is mailed, usually in mid-August. An informal conference with the property appraiser does not extend that deadline, per the Florida Department of Revenue.
Everywhere else: look up the county board of review or assessment appeals board and its filing window, which often opens only once a year.

Winning appeals rely on evidence: photos of the condition, repair estimates, recent sales of comparable properties, and the closing statement from a recent purchase. The Texas Comptroller is blunt that an owner cannot just show up and say the district is wrong. For complex or high-value appeals, a property tax consultant or attorney who handles appeals in that county is worth talking to.

Where beginners lose money with assessed values

Quoting the seller off the tax card. In a capped state, a seller who sees your offer next to a low assessment may feel it is generous, until a neighbor’s sale tells them otherwise and they cancel. In an uncapped, lagging county, the assessment may be higher than as-is value and your offer looks insulting. Anchor every conversation in comps instead.
Ignoring the tax reset in the buyer’s numbers. As the example shows, one line can erase most of the cash flow.
Assuming the homestead exemption carries over. It belongs to the owner-occupant, not the house.
Using the assessor’s square footage and bedroom count without checking. Assessor records miss additions and conversions, and sometimes count spaces that were never permitted. Verify on the walkthrough, and see which areas lenders actually count in our price per square foot guide.
Treating a low assessment as proof of equity. Check recorded liens. A low assessed value tells you nothing about a second mortgage or a judgment.
Forgetting prorations and supplemental bills. In California, a supplemental bill can arrive months after closing. Make sure your end buyer and your title company know who owes what on the settlement statement.

If you want feedback on how you underwrite deals, including tax resets, the mentorship program is one place to get it.

Questions investors ask about assessed and market value

Is assessed value usually lower than market value?

Often, but not always. States with assessment ratios (Illinois at 33 1/3%, Michigan at 50%) produce assessed values well below market by design, and caps widen the gap over time. In a falling market, or on a house in poor condition, assessed value can exceed what the property would sell for.

Can I use the assessor’s market value instead of comps?

Use it as a rough sanity check only. It is a mass-appraisal estimate as of a fixed date, often without an interior inspection, and IAAO standards accept a meaningful margin of error. Comps from the last few months tell you what buyers are paying now.

Does a wholesale assignment trigger reassessment?

Assigning a purchase contract does not transfer title, so the trigger is the deed from the seller to your end buyer. A double close records two deeds on the same day. Either way, the end buyer is the new owner the assessor will reassess, so build that reset into their numbers and let the title company handle tax prorations.

When does Michigan’s taxable value uncap?

In the tax year after a transfer of ownership, taxable value resets to the state equalized value (about 50% of true cash value) and then caps again going forward. Buyers must file a Property Transfer Affidavit with the local assessor within 45 days of the transfer.

Is a Zestimate closer to market value than the assessment?

Sometimes, because AVMs update more often, but neither can see condition. For distressed property, negotiate from your own comp work.

Does the sale price I record affect the next assessment?

Yes, in most places. Recorded sale prices feed the assessor’s sales data, and in California the sale price is presumed to be market value for the new base year. Some states also collect a transfer tax tied to the price.