How Accurate Are Zillow Zestimates? (2026)

Every agent has had the conversation. A seller pulls up Zillow, points at the Zestimate, and says “My house is worth $475,000.” The Zestimate says so. Your CMA says $430,000. Now you need to explain why a computer is wrong without sounding defensive or dismissive.

The short answer: Zillow’s Zestimate has a national median error rate of about 2.4% for on-market homes and 7.5% for off-market homes (as of Zillow’s own published data). That means for a $400,000 home, the Zestimate could be off by $10,000-$30,000 in either direction — and that is the median. For individual properties, the error can be much larger.

What Is a Zestimate?

A Zestimate is Zillow’s automated valuation model (AVM). It uses public and MLS data — tax records, prior sale prices, property characteristics, comparable sales, location data, and market trends — to estimate a home’s value. Zillow processes this through a neural network model trained on millions of transactions.

Zillow does not inspect the property. It does not see the updated kitchen, the water stain on the ceiling, or the new HVAC system. It works with data, and data has gaps.

For a broader overview of how AVMs work across all platforms, read our automated valuation model guide.

Zestimate Accuracy by the Numbers

Zillow publishes its accuracy metrics. Here is what they report:

“On-market” means the home is currently listed for sale. Zillow’s model performs better here because it incorporates the listing price, which is itself informed by an agent’s CMA. In other words, the Zestimate is most accurate when an agent has already done the hard work of pricing the home.

“Off-market” is where sellers actually look at their Zestimate — when they are thinking about selling but have not listed yet. And that is where the 7.5% median error applies. On a $500,000 home, 7.5% is $37,500.

Why Zestimates Are Wrong

Zestimates fail for predictable reasons. Understanding these helps you explain the gap to clients.

1. Condition and Updates Are Invisible

Zillow knows your home has 3 bedrooms and 2 bathrooms. It does not know you spent $80,000 on a kitchen remodel or that the original 1985 carpet is still in the bedrooms. Two identical-on-paper homes in the same neighborhood can differ by $50,000-100,000+ based on condition alone.

2. Unique Properties Break the Model

AVMs work by comparison. When there are few comparable properties — custom homes, large acreage, waterfront, historic properties, mixed-use — the model has less training data and accuracy drops. In rural areas with few recent sales, Zestimates can be off by 20% or more.

3. Hyperlocal Factors Are Not in the Data

• The lot backs to a busy commercial road (–$20,000-40,000)
• The house is on a cul-de-sac (+$10,000-20,000)
• The neighbor has a junkyard in their backyard (–$30,000+)
• The school district boundary runs through the neighborhood (homes on one side of the street worth more)
• A new development is planned nearby (+ or – depending on type)

None of these show up in Zillow’s data. They all show up in your CMA.

4. Data Errors

Tax records — the primary data source for AVMs — contain errors. Square footage discrepancies between tax records and actual measurements are common. A finished basement may not be counted in the official square footage. An added bedroom or bathroom may not have been permitted and updated in records.

5. Market Timing

Zestimates update frequently, but they lag behind fast-moving markets. In a hot seller’s market where prices jump 5% in a month, the Zestimate may be a month behind. In a cooling market, it may be slow to adjust downward.

How Zestimates Compare to Other AVMs

Zillow is not the only AVM. Here is how the major automated valuations compare:

Redfin claims a slightly lower median error than Zillow, primarily because their model weights MLS data more heavily. HouseCanary, a professional-grade AVM, incorporates permit data and more granular market indicators but is not free for consumers.

How to Talk to Clients About Zestimates

This is the practical skill every agent needs. Here are the conversations you will have:

The Seller Who Thinks the Zestimate Is Their Home’s Value

What they say: “Zillow says my house is worth $475,000.”

What to say: “The Zestimate is a starting point, and I always check it before a listing appointment. But it has a 7.5% margin of error for homes that are not listed — that is plus or minus $35,000 on your home. It also cannot see inside your home. Let me show you what actually sold in your neighborhood in the last 90 days, because buyers are going to compare your home to those — not to what Zillow says.”

Then walk them through your CMA. Let the data do the talking.

The Buyer Who Thinks a Home Is Overpriced Based on the Zestimate

What they say: “The list price is $450,000 but Zillow says it is only worth $420,000.”

What to say: “Zestimates can be off by 5-10% on any given home. The listing agent priced this based on comparable sales and the home’s actual condition. Let me pull the comps so we can see if the list price is supported by recent sales. If it is not, we will use that in our offer strategy.”

The Seller Whose Zestimate Jumped After You Listed

What they say: “My Zestimate went up $20,000 since you listed my house. Should we raise the price?”

What to say: “That happens because Zillow incorporates your listing price into the Zestimate. It is essentially reflecting your pricing decision back to you, not providing new information. The real test is buyer activity — showings, offers, and feedback from agents who have seen it.”

When Zestimates Are Useful

Zestimates are not useless. They have legitimate applications:

• Quick screening for investors. If you are scanning 50 properties, Zestimates help narrow the list before running full CMAs.
• Trend tracking. Watching a Zestimate trend over 12 months shows general market direction for a neighborhood.
• Client conversation starter. “What does Zillow say?” opens the door to discussing pricing, which is where your expertise comes in.
• Sanity check on your CMA. If your CMA says $450,000 and the Zestimate says $380,000, investigate the gap. You might be right, but you should know why the model disagrees.

Zestimate Accuracy by Property Type

Property Type	Zestimate Reliability	Why
Subdivision homes (cookie-cutter)	Highest	Many similar comps, uniform data
Urban condos	High	Consistent sizes, recent sales in same building
Older homes in diverse neighborhoods	Medium	Variable condition, mix of updated and original
New construction	Medium-low	No prior sale history, builder pricing vs. resale
Luxury homes ($1M+)	Low	Few comps, unique features, condition matters enormously
Rural properties (5+ acres)	Low	Few comps, land value varies, outbuildings
Multi-family	Low	Income approach matters more than comp approach
Custom/unique architecture	Very low	No comparable properties exist

If your client’s home falls in the “low” or “very low” categories, lead with that. “Zillow works best for subdivision homes where there are 20 identical houses that sold recently. For a home like yours, the model just does not have enough data.”

Related

• Automated Valuation Model Guide for Agents — how AVMs work, their accuracy, and the best tools
• How to Do a CMA in Real Estate — step-by-step guide to building your own comparative market analysis
• Homesage AI vs HouseCanary vs Cloud CMA — professional property analysis tools compared
• AVM in Real Estate — business impact of automated valuations