The Zestimate is a useful starting point, but it is not a price. Zillow says so itself: it is "not an appraisal," and for homes that are not listed for sale, its own nationwide median error is 7.20 percent. That means half the time the Zestimate is within 7.20 percent of what the home actually sells for, and half the time it is further off.
Before real estate, I worked as a financial analyst in London. In that world, nobody priced an asset from a single model output without asking what the model could see and what it could not. I bring the same habit to every listing conversation, and this is how I explain the Zestimate to sellers.
What is the Zestimate, exactly?
In Zillow's words, the Zestimate is "Zillow's estimate of a home's market value." It combines public records, MLS data and details owners submit, and runs them through Zillow's own valuation model.
That is a reasonable way to estimate millions of homes at once. It is not the same as studying one home. A model works from what is recorded about a property, and a lot of what makes one house sell differently from the house next door is never recorded anywhere.
How far off can it be?
Zillow publishes its own accuracy figure. As of October 2026, its Zestimate page lists a nationwide median error of 7.20 percent for off-market homes. A median error is the midpoint: half of homes land closer than that, and half land further away.
To put that in dollars, take a home worth $750,000 as an illustration. Seven point two percent is about $54,000. So even when the model is having an average day, the gap between the Zestimate and the eventual sale price can be the difference between a strong offer and a long time on the market.
As an analyst, that is the part I want every seller to hear. A median error tells you the estimate is a range, not a number. Treating it as a number is where pricing mistakes start.
What can't the Zestimate see?
Zillow's own help page is candid about this: "Unreported additions, updates and remodels aren't reflected in the Zestimate." It also says accuracy depends on how much data it has for your home and your area.
In practice, these are the things I see a model miss most often in the East Bay:
- Condition. A remodeled kitchen and an original one look the same in county records.
- Permitted versus unpermitted work. A buyer's lender and appraiser care about the difference. The model usually does not know.
- The lot itself. Backing onto open space, a busy road or a sound wall changes what buyers will pay.
- Special taxes and HOA costs. Two similar homes can carry very different Mello-Roos or HOA bills, and buyers price that in.
- Leased solar and other obligations. These affect a sale but rarely show up in the data a model reads.
If the Zestimate is not my price, what is?
Your price comes from what buyers have recently paid for homes that are truly comparable to yours: same area, similar size, age, lot and condition, sold recently. That is the comparable sales method, and it is what an appraiser will use when your buyer's lender orders an appraisal.
I read those sales the way I used to read a portfolio: what is genuinely comparable, what needs an adjustment, and how much is a judgment call. Then I set a price for the market we are actually in, not the one the model last saw. I walk through the method in more detail in How to Price Your Brentwood Home Competitively.
Is the Zestimate ever useful?
Yes. It is a free, fast starting point, and Zillow describes it that way. If your Zestimate looks too high or too low, it is a good prompt to check that Zillow has your home's facts right, and then to ask for a real valuation.
What I ask sellers not to do is anchor on it. A price set from the Zestimate tends to drift toward whichever number the owner prefers, and the market corrects that quickly.
Frequently asked questions about the Zestimate
Is the Zestimate an appraisal?
No. Zillow says the Zestimate is not an appraisal and can't be used in place of one. A lender orders an appraisal from a licensed appraiser, who studies comparable sales and the home itself.
How accurate is the Zestimate?
As of October 2026, Zillow lists a nationwide median error of 7.20 percent for off-market homes. Half of homes sell within that range of the Zestimate and half sell further from it.
Why is my Zestimate wrong?
Zillow says unreported additions, updates and remodels aren't reflected, and accuracy depends on how much data it has for your home and area. Condition, the lot, special taxes and leased solar are common gaps.
How should I price my home instead?
Use recent sales of truly comparable homes nearby, adjusted for size, condition and lot. That is the same method an appraiser uses, and it reflects the current market.
The Bottom Line on the Zestimate
The Zestimate is a model's estimate with a published median error of 7.20 percent for off-market homes, and Zillow says it is not an appraisal. Use it as a starting point. Price from recent comparable sales and an honest read of your home's condition, lot and costs, because that is what buyers and appraisers will do.
Want a real number for your home?
I'll prepare a comparable sales analysis for your home, explain every adjustment, and show you where the Zestimate and the market differ. Request a free home valuation, or call or text me at 925-250-9611. I speak English, Punjabi and Hindi.
Sources
- Zillow, "What is a Zestimate?" (accessed October 2026): definition, "not an appraisal," nationwide median error for off-market homes, and the note that unreported additions, updates and remodels aren't reflected.
Jaz Chand, Broker Associate | Homes With Accent
The Jaz Team at Merrill Signature Properties | DRE #01751823
Phone/Text: 925-250-9611 | Jaz@HomesWithAccent.com
General information only. Zestimate figures are Zillow's own, as published on its website in October 2026, and may change. A home's value depends on its specific facts and the current market.