No published figure says how accurate a home value estimator is for a particular Claremont house. Where a provider publishes accuracy at all, it states a median error across many homes in a state or a metro: the estimate lands within that percentage of the later sale price for half of the homes measured, and further off for the other half. An estimator's result is an automated estimate, and it is not an appraisal. The stated error range tells you how the model does on average, not where your house falls.
This article belongs to the online estimates vs. appraisals series. It answers the question often asked as "how close is Zillow to actual value?" Every figure below is quoted from the provider's own page with the date it was read, because the figures change.
What do the providers publish?
Redfin publishes the most detail. Its Redfin Estimate page, read on November 6, 2026 and showing a last-updated date of November 5, 2026, stated a median error rate of 1.93% for on-market homes and 7.59% for off-market homes across all locations. In Redfin's words, for off-market homes the estimate "will be within 7.59% of the eventual sales price half the time." The page also lists rows by state. The California row read that day:
Redfin, California row (read November 6, 2026)Median errorWithin 5%Within 10%Within 20%
On-market (listed for sale)
2.00%
79.57%
92.76%
98.11%
Off-market
6.72%
39.61%
64.73%
85.61%
Redfin updates the table weekly, so the page will show different numbers on another day. Read the current table before relying on any of them.
The other pages publish no figure. Opendoor's home value estimator says "Accuracy depends on your home and the available data." HomeLight's home value estimator page says such estimates are "only approximations, not formal appraisals." Zillow's Zestimate page refused automated retrieval on November 6, 2026, so no Zillow figures are quoted here. Read that page directly, and note the date you read it.
How do you read a median error?
- Half of homes are further off. A median is the middle result, and Redfin's own wording, "half the time," says so. The figure cannot tell you which half your house is in.
- The "within" columns show the tail. In the California off-market row, 85.61% of estimates were within 20% of the sale price.
- On-market and off-market are different questions. Redfin explains the gap itself: its estimate "is more accurate for homes that are for sale because there is more data available about those homes." A listed house has a list price and a fresh description for the model to read. Most owners asking what their house is worth are asking about an off-market house.
- The geography is broad. Redfin's table runs by state, plus an all-locations total. No row covers Los Angeles County, San Bernardino County or Claremont, and a California figure blends every kind of market in the state.
- The test is a sale. Accuracy is measured against later sale prices, so it describes houses that sold during the measurement, not the long-held houses that did not.
What is a confidence range, and how is it different?
A confidence range is the spread of values within which a model expects the sale price of one property to fall. The median error describes the model across many homes; the range describes how sure it is about yours. Opendoor, for example, presents its result as an estimated value range and advises using "the range as a starting point." A wide range is the model saying it has little to go on.
Why might a Claremont house sit in the far half?
Error follows data. Redfin says inaccurate estimates happen "usually because we don't have as much data on that home." In Claremont that points at particular houses, the kinds that come in:
- Pre-1940 Craftsman and Spanish Colonial Revival houses near the Village and the Colleges, where enclosed porches and later additions may differ from the recorded area, as in estimate vs. appraisal for a Claremont Village bungalow.
- Hillside and custom homes in Claraboya and Padua Hills, which sell on view, grade and access and have few similar sales nearby; see why a home value calculator misreads hillside homes.
- Houses near Mills Avenue and Claremont Boulevard, where a model may draw on Montclair or Upland sales across the county line; see when Montclair sales leak into a Claremont estimate.
- Newer infill in the Village expansion, with a short sales history of its own kind.
Postwar ranch tracts north of Foothill Boulevard, which repeat a handful of layouts on similar lots, give a model more to work with, though an addition or a garage conversion still escapes it. None of this says how far any one estimate is off. Only the house and its sales can say that.
Do lenders rely on these numbers?
Some lending decisions use an automated valuation model (AVM), a computer program that predicts value from data about a property and the sales near it, and federal regulators govern that use. On July 17, 2024, six federal agencies announced a final rule requiring institutions that use AVMs for certain mortgages secured by a consumer's principal dwelling to adopt quality control standards designed to "ensure a high level of confidence in estimates," "protect against data manipulation," "seek to avoid conflicts of interest," "require random sample testing and reviews," and "comply with nondiscrimination laws" (Federal Reserve press release). Whether a lender uses an AVM or orders an appraisal is the lender's decision. AVM vs. appraisal explains the difference.
What an appraisal offers in place of an error rate
An appraisal carries no published error rate, because it is not a statistical prediction. It is an opinion of value, the conclusion about market value a licensed or certified appraiser reaches and signs as of an effective date, the date the opinion applies to, written for an intended use, what the report will be used for, and intended users, the people entitled to rely on it. In place of an error band it shows its work: gross living area measured on site, condition and quality observed, comparable sales chosen with reasons, and each adjustment explained. A reader can check every step, and a reviewer can question any of them.
Four numbers that are not appraisals
An automated estimate is not an appraisal. An agent CMA, the comparative market analysis a licensed real estate agent prepares to suggest a list or sale price, is not an appraisal. A county assessment, the taxable value the assessor sets under California's assessment rules, is not an appraisal. A cash offer, the price a buyer will pay on stated terms, is not an appraisal. The appraisal vs. estimate page sets all five side by side, and the pillar, what an online estimate cannot see in Claremont, covers the blind spots pocket by pocket.
Next step
If a Claremont house needs a value that someone else will read, the Claremont area page describes its pockets, and you can request an appraisal or call (909) 324-6122. The fee is set by the scope of the assignment and quoted before work begins, and it does not depend on the value.
Sources
- Redfin, Redfin Estimate (not a formal appraisal; how comparable homes are chosen; accuracy tables, page marked "Last updated 11/05/26") (accessed November 6, 2026)
- Opendoor, home value estimator (automated valuation model; does not inspect the home; value range) (accessed November 6, 2026)
- HomeLight, home value estimator (approximations, not formal appraisals) (accessed November 6, 2026)
- Zillow, Zestimate page (attempted November 6, 2026; the page refused automated retrieval, so it is not quoted)
- Board of Governors of the Federal Reserve System, press release on the interagency final rule on quality control standards for automated valuation models (July 17, 2024) (accessed November 6, 2026)
- The Appraisal Foundation, Uniform Standards of Professional Appraisal Practice (USPAP) (accessed November 6, 2026)
- California Bureau of Real Estate Appraisers, license lookup (accessed November 6, 2026)
Gordon Hall, California Certified Residential Real Estate Appraiser, BREA No. AR003877 (lookup: https://www2.brea.ca.gov/breasearch/faces/party/view.xhtml?id=23601). Reports are prepared in conformity with the Uniform Standards of Professional Appraisal Practice (USPAP). Nothing here is legal or tax advice; admissibility is always the court's decision.
Frequently asked questions
How close is Zillow to actual value?
Zillow's Zestimate page refused automated retrieval when this article was written on November 6, 2026, so no Zillow accuracy figures are quoted here. Read that page directly and note the date. Any published median error describes many homes, not one, and half of homes land further off than the median.
What does a median error rate mean for my house?
A median error rate is the middle result across many estimates compared with later sale prices: half landed within that percentage of the sale price and half did not. It cannot say which half a particular house is in, so it describes the model, not your house.
Is a home value estimator more accurate when the house is for sale?
Providers say so. Redfin's page states its estimate is more accurate for homes that are for sale because there is more data available about them, and its published on-market error is lower than its off-market error. Most owners asking what a house is worth are asking about an off-market house.
Is there an accuracy figure for Claremont specifically?
Not on the estimator pages read for this article. Redfin's accuracy table, read on November 6, 2026, runs by state with an all-locations total, and Opendoor and HomeLight publish no figure. A figure for the whole state blends many kinds of markets and says nothing about one Claremont pocket.
