Why Is My Online Home Value So Different From What the Agent Said?

A free estimator says $395,000; a week later an agent at your kitchen table says $470,000. One of them must be wrong, you think, probably the one that costs you $75,000. Both numbers were produced the same way, by picking a few recent sales and adjusting them; they disagree because the picking and adjusting used different data and different motives. This page shows where each number comes from, how to tell which is closer, and when the gap matters legally. The wider picture is in the guide to how much is my house worth.

Why the online number and the agent's number are built from different sales

Every home value that is not an actual sale is an estimate built from other people's sales. The question is which sales, and what was done to them.

The online estimator works from what it can read without visiting: assessor and recorder data (year built, square footage, lot, last recorded price), listing feeds where the company has them, and whatever an owner has typed in. A statistical model finds sales it considers similar, weights them and prints a figure.

The agent opens the MLS, pulls closed sales from the past six to twelve months on streets they know, drops the ones they consider unlike yours, and writes a comparative market analysis (CMA). Three to six sales, hand-picked, and the picking is where judgment and interest enter.

The appraiser works under the tightest rules of the three. Fannie Mae's Selling Guide requires a minimum of three closed comparables, says sales that closed within the last 12 months should be used, and makes the appraiser responsible for choosing the best and most appropriate ones¹. Each adjustment must reflect the market's reaction to the difference between the properties; Fannie Mae sets no limits on net or gross adjustments and calls a standard per-square-foot figure inappropriate where market analysis shows a different one².

So three people can each start from a defensible set of sales and end $75,000 apart. The companion piece on how accurate online home value estimators are covers the error rates the portals publish.

Does the online tool know about my new kitchen?

Usually not, and for an improved or neglected home this is the largest single source of the gap.

Public records carry what a permit or a deed recorded: year built, square footage, lot, and the date and (in most states) the price of the last sale. They do not record the roof you replaced in 2022, the kitchen you gutted in 2024 or the basement that has been damp for a decade. A model that has never seen your house assumes an average condition for its age and street.

Appraisers are not allowed to assume. Fannie Mae's condition ratings run from C1 (new, never occupied) to C6 (substantial damage affecting safety or structural integrity); C3 describes improvements that are well maintained with limited physical depreciation from normal wear and tear, C4 some minor deferred maintenance and physical deterioration from normal wear and tear³. One step on that scale, from C4 to C3, is often the whole difference between an estimator that assumed average and an agent who stood in your renovated kitchen.

The reverse happens too: the agent sees the kitchen and forgets the roof, while the model, which saw neither, lands lower and by accident closer. The guide to what increases home value lists the features that move prices and their coefficients.

Why the gap is wider in some states and on some streets

Where closed prices are not public. Texas does not require sale prices to be reported to its appraisal districts and, as the state Comptroller's office puts it, is one of only a handful of states that do not⁴. An online model there works from listing prices, tax values and whatever owners volunteer; the agent's MLS shows the agreed prices.

Where few similar homes sell. Five acres, the only two-story on a street of ranches, two sales a year: thin evidence makes a wide estimate, and the tools rarely say so.

Where prices have moved since the sales closed. A sale from ten months ago is evidence about ten months ago. The FHFA House Price Index tracks price changes in repeat sales and refinancings of the same single-family homes from Fannie Mae and Freddie Mac mortgage data, down to county, ZIP code and census tract level, and is the official way to bring an older sale up to date⁵. Even licensed appraisers do this inconsistently: an FHFA study of purchases from the third quarter of 2018 through the fourth quarter of 2021, years of strong price growth, found that appraisers time-adjusted at least one comparable for only 18.5 percent of the properties⁶. If professionals under written standards disagree about time adjustments, a free model and an agent working from memory will disagree more.

Is the agent's number too high just to win my listing?

Sometimes, and you are right to ask. The listing appointment is a sales call, and the price is pitched in two directions at once: to you, so you sign, and later to buyers, so the house sells. The industry's own rulebook recognizes the temptation. Standard of Practice 1-3 of the National Association of REALTORS® Code of Ethics, whose current edition took effect on January 1, 2026, bars members from deliberately misleading an owner about value while they compete for the listing⁷. The pattern it forbids is familiar: quote high, win the listing, then ask for price cuts once the house has sat for six weeks.

How to tell an honest CMA from a pitch:

1. Ask for the sales, not the conclusion. Closed sales with addresses, dates, square footage and the adjustments made are evidence. A single page with a suggested list price is marketing.
2. Look at which sales were left out. If the lowest recent sale on your street is missing, ask why.
3. Check the dates. Sales older than a year need a time adjustment and an explanation, the standard an appraiser works to¹.
4. Ask what the agent expects the house to appraise for. An honest agent will say whether a lender's appraiser is likely to agree.
5. Compare the list price with the market tempo. Homes sold in August 2026 had typically been on the market for 31 days, with 4.9 months of unsold supply nationally⁸. With that much choice an overpriced listing is found out quickly.

How to set a price that sells is in the guide to pricing strategy for your listing.

Example: a $75,000 gap on a house near the national median

The figures below are a hypothetical example built around the national median existing-home price of $429,100 that the National Association of REALTORS® reported for August 2026, up 1.6 percent from a year earlier⁸. They are not a real address.

The house: 1,850 square feet, three bedrooms, built 1994, suburban street, kitchen and baths remodeled in 2024, original roof. The online estimate says $395,000. The agent says $470,000.

The model's low figure comes from the four distant sales and the C4 assumption; the agent's high figure comes from dropping Sale B and treating your house as the equal of Sale C, which is bigger and sits on more land. Adjusted, the picture tightens: Sale A, seven months old, moved to today's level at the 1.6 percent annual pace is roughly $445,000⁸; Sale B needs an upward condition adjustment for your remodel; Sale C a downward one for its extra 100 square feet and its lot. Three adjusted sales land between about $440,000 and $455,000. Neither original number was inside that band, and the model's was the further out.

In this example about $50,000 of the gap was the model undervaluing the remodel and about $25,000 was the listing pitch.

Which number is closer to what a buyer will actually pay?

Neither, until a buyer signs, and even then the sale is tested once more: where the buyer finances the purchase, the lender's appraiser pulls their own three or more closed sales¹ and the contract price is compared with the result.

FHFA builds its Uniform Appraisal Dataset aggregate statistics from more than 47 million appraisals submitted to Fannie Mae and Freddie Mac, and reports that the share of purchase appraisals coming in below the contract price rose from 8.4 percent in 2013 to 15.2 percent in 2021⁹. The buyer's enthusiasm, the agent's list price and the appraiser's evidence are three different things, and the online estimate is a fourth.

So the honest answer to "which one is right" is: the one that survives contact with three adjusted closed sales.

How to check both numbers in an afternoon

1. Get the closed sales yourself. Same neighborhood, within about 20 percent of your square footage, closed in the last 12 months, the window Fannie Mae sets for appraisals¹. Recorder websites show closed prices in disclosure states; elsewhere ask the agent for the MLS sheets. The guide to finding comparable sales shows where to look.
2. Put every sale on a price per square foot. The agent's $470,000 in the example works out to $254 per square foot, while the highest closed sale on that street reached $245; a figure no closed sale has matched is one the agent owes you an explanation for. Why smaller homes carry a higher figure is in the price per square foot guide.
3. Move older sales to today. Apply the FHFA index change for your metro, county or ZIP code since each sale closed⁵.
4. Rate the condition honestly. Walk your house with the C1 to C6 definitions in hand³ and rate each comparable from its listing photos. Adjust for the difference, not for what you spent.
5. Write the adjustments down. Fannie Mae wants adjustments that reflect the market's reaction to a difference²; a sale with and a sale without the feature on the same street is the evidence, not a rule of thumb.
6. Ask the agent to explain the residue. Nobody answers for the online estimate, but the agent can walk you through every sale they excluded.

If both numbers fall inside your adjusted range, the gap was mostly noise. If one sits outside, distrust that one.

When the gap stops being academic: lender, court, tax office

For most owners the gap matters once, when it decides whether to sell; in three situations it carries legal weight and neither estimate counts. A buyer's lender commissions its own appraisal under the Fannie Mae or Freddie Mac standards described above¹, and that figure decides the loan; if it lands below the agreed price, the guide on what to do when an appraisal comes in low covers rebuttals and renegotiation. In a divorce, a probate or a quarrel between heirs, the judge expects a signed appraisal with a stated effective date, not a screenshot or a CMA produced to win a listing. In a property-tax appeal or an estate-tax filing, the taxing authority again expects a licensed appraiser's work.

Treat both numbers as preparation for those conversations: they tell you which sales to bring. This is general information, not legal or tax advice.

What a CheckValue report shows about where its number comes from

CheckValue produces an AI valuation report, so it is a model as well, and it does not claim to be the referee between your two numbers. It removes hidden evidence and hidden assumptions, the two things that make the gap impossible to argue about.

• The comparable sales are printed. You can lay them next to the agent's CMA and see which sales each used and which each ignored.
• The condition is yours, not an assumption. You confirm the facts about the house yourself, condition included, and your own photos are read for condition, plot and surroundings. Each adjustment appears with its coefficient and its source.
• The index and the tempo are on the page. The official price index, the district average per square foot and the time to sell sit beside the point value and its range, with every source numbered.

How an AI valuation works describes the comparables, adjustments and plausibility checks, and the page on how results stay consistent explains what the report can and cannot tell you. Nobody from CheckValue will call you and the address is not passed to anyone; the person who orders the report is the customer, which is what lets it show its work without a pitch attached. The free preview of your report lays out that structure for your address before you pay anything.

What it is not: a licensed appraisal. Nobody inspects the house, and when a lender, a court or a tax authority is involved, the appraisal is theirs to order. For deciding which of your two figures deserves trust, three printed comparable sales do more than a fourth opinion would.

This article is general information, not legal, tax or investment advice. Figures and rules carry the year they were published; check the cited source for the current version.

Christian Eckmair

Co-founder, CheckValue · Managing director, CBDNOL GmbH · More than 20 years in real estate in Tenerife and Austria · Reviewed by Josef Eckmair MBA

Christian Eckmair is co-founder of CheckValue and managing director of CBDNOL GmbH (Ansfelden, Austria). He has worked in real estate for more than 20 years in Tenerife and Austria – buying, renovating, letting and selling residential property – and writes about home values, buying checks and ownership records.

Articles by Christian Eckmair →

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