Zillow is one of the leading real estate websites in the US. One feature it's known for is its Zestimate, which offers nationwide home value estimates.
Unfortunately, a Zillow Zestimate isn't all that accurate. The company says its current median error rate is 1.94% for on-market homes and 7.06% for off-market properties. That means an off-market home valued at $1 million could be off by as much as $70,000. Zillow also notes that half of all on-market homes are within the median error vs. the selling price, and half aren't.
“They can be ballpark accurate in certain areas, especially in subdivisions where homes are similar and sales are frequent. But in more rural areas or when homes are unique and don’t have good comps, they can be way off. I’ve seen them miss the mark by six figures," says Mathias John, Realtor based in Charlottesville, VA.
The bottom line: A Zestimate is just an estimate, and it isn't intended to replace more accurate valuation methods like a comparative market analysis (CMA) report or an appraisal. If you need an accurate home value estimate, we highly recommend contacting an experienced local realtor for a free CMA. It will give you the most accurate evaluation so you can get the best sale price for your home. Simply fill out this short quiz to get matched with local agents today!
How accurate is a Zestimate?
| Type of home | Median error rate |
|---|---|
| On-market | 1.94% |
| Off-market | 7.06% |
A Zestimate is Zillow's estimated market value for a home. Zillow has calculated Zestimates for 116 million homes nationwide.
Zillow's Zestimates are intended as estimates. Their accuracy varies based on location and the availability of local data. The more publicly available data in a given area, the more accurate the Zestimates will be.[1]
Zillow publishes its data coverage and estimated margin of error for specific areas. For example, the median error rate for off-market homes in Colorado Springs is 4.62%, but in Cleveland, it's 9.10%.[1]
Factors impacting Zestimate accuracy
A Zestimate's accuracy also varies based on the constitution of the town or neighborhood where a property is located. If a home is situated in a new development with similarly priced homes, it will probably be fairly accurate. However, older or more unique homes can throw the algorithm off.
“I listed a home in the Blue Ridge Mountains – Zillow had a property estimated at $650,000, and we sold it for well over $1.1 million," says John, the agent based in Charlottesville, VA.
The Zestimate missed the mark, because it didn’t account for the home's mountain setting, the design, or the premium interior. "This shows me that real-world context matters much more than a computer model," he says.
Zillow and Redfin consistently misread high-end properties because they can't grasp what actually matters to wealthy buyers, according to Wesley Kang, founder of Realtor 1099 Cafe.
"A Zestimate might look reasonable on paper but miss the features that command top dollar in luxury markets," he says.
📉 Even Zillow's CEO couldn't trust the Zestimate
In 2016, then-Zillow CEO Spencer Rascoff sold his Seattle home for $1.05 million — nearly 40% less than its Zestimate of $1.75 million at the time.[2] The home’s unique lot and location on a busy road threw off the algorithm, exposing just how far off Zillow’s estimates can be — even for the company’s top executive.
Zestimate accuracy has likely improved since then, as reflected in its lower median error rates. But stories like this remain a clear reminder: Zestimates are a starting point, not a pricing strategy. For a more accurate home value estimator, connect with a local realtor for a CMA report. Simply fill out this short quiz to get matched with local agents today!
How is a Zestimate calculated?
Zillow Zestimates are automatically calculated using a proprietary formula that merges data from several sources, including public data and user-submitted information.
| Type of data | Examples |
|---|---|
| Home characteristics | Location, square footage, number of bathrooms, special features and amenities |
| On-market data | Listing price, description, days on market |
| Off-market data | Tax records, age of the home, what the home sold for previously, appraisal values |
| Market trends | Seasonal changes in buyer demand |
The company uses this information and the same information for homes in the surrounding area. It combines it with data it receives from homeowners to come up with approximate valuations for real estate.
“Online estimators don’t factor in things like condition, upgrades, layout, buyer perception, market timing, or even school districts," explains Mathias John, a realtor based in Charlottesville, VA. "A good CMA gives sellers the ‘why’ behind the number, not just a blind guess.”
Zillow vs. Redfin estimators
| Estimator | On-market error rate | Off-market error rate | Update frequency |
|---|---|---|---|
| Zillow | 1.94% | 7.06% | Varies by property |
| Redfin | 1.98% | 7.72% | Daily (on-market), weekly (off-market |
Both Zillow and Redfin offer free home value estimates based on automated valuation models (AVMs), but there are some key differences in accuracy and approach.
While Zillow currently edges out Redfin slightly on accuracy, the difference is marginal, and both tools have limitations.
“Redfin tends to be a little closer in my experience — especially in cities or larger suburbs. Zillow often overshoots, sometimes by a lot. But it often depends on the type of home and the area," John says.
Zillow has wider national coverage, but it doesn’t always have access to local MLS data in every market — which can lead to larger errors in some areas. Redfin, as a brokerage, has direct MLS access in areas where it operates, which may give it an edge in specific markets.
Ultimately, both platforms are best used for ballpark estimates.
» How accurate is a Redfin home value estimate?
Zestimate pros and cons
Pros
- It's free and easy
- You don't need to contact an agent
Cons
- Not always accurate
- Important factors like home improvements can be missed
There are a lot of ways that Zestimates can help both current and prospective homeowners. A Zestimate is free and easy to obtain and allows people to look at an estimated value of a home without having to go through a professional.
Home value estimators like Zestimate have become much more accurate in recent years, but they aren't a substitute for more accurate valuations. If you're considering buying or selling property, a Zillow Zestimate is a great place to start.
The main negative of a Zestimate is that it's entirely calculated using artificial intelligence. Buying a home is a personal decision, and there are many variables that can't be quantified. There are many factors specific to a property or locale that Zillow isn't privy to.
With current technological limitations, an AI system like Zestimate is bound to miss some factors, like recent home renovations, and sometimes, those factors significantly affect a home's value.
More accurate ways to determine your property value
Get a comparative market analysis
A CMA report is one of the most effective ways of evaluating a home's market value.
To conduct a CMA, a real estate agent compares a property and all of its features to similar current, expired, and sold listings in the area. With this information, they can get a good idea of what local buyers will pay.
"A CMA goes far beyond what an algorithm can do. It combines public data with real-world insights and local market experience," John says.
Home value estimators are a good starting point to gauge your home's worth. But when you're ready to get a more accurate home value estimate, work with an experienced local realtor. A real estate agent is best positioned to know how much a property will likely sell for.
"After years in this market, I’d trust an experienced agent’s CMA over any digital estimate," Kang says.
Whether you're a prospective buyer or seller, a free service like Clever Real Estate can connect you with top local agents who conduct expert CMAs.
Get an appraisal
An appraisal by a licensed appraiser is another way to calculate a home's worth. State and local governments commonly use appraisals to determine the property tax rate and mortgage lenders to ensure a home is a good investment.
Appraised value and market value are not the same thing. A home's appraised value can differ from its market value, particularly in a fast-moving market. If a location has high demand and low supply, an appraisal may not accurately reflect how much prospective buyers will pay.
You can also get a pre-listing appraisal (for $400-600) to help you set the best listing price for your home, although in most cases, a CMA report is good enough (and free).
