What is a Zestimate?

The latest Zestimate model is our most accurate Zestimate yet. It’s based on a neural network model and uses even more historical data to produce off-market home valuations. This means the Zestimate is more responsive to market trends & seasonality that may affect a home’s market value. We also reduced overall errors and processing time in the Zestimate.

The amount of data we have for your home and homes in your area directly affects the Zestimate’s accuracy, including the amount of demand in your area for homes. If the data is incorrect or incomplete, update your home facts — this may affect your Zestimate.

To ensure the most accurate Zestimate, consider reporting any home updates to your local tax assessor. Unreported additions, updates and remodels aren’t reflected in the Zestimate.

Check that your tax history and price history (the sale price and date you bought your home) are accurate on Zillow. If data is missing or incorrect, let us know.

Be aware that the model that creates the Zestimate factors in changing market trends, including seasonal fluctuations in demand. So in some cases that may be the reason for a change in your Zestimate.

When a home goes on the market, new data can be incorporated into the Zestimate algorithm. In the simplest terms, the Zestimate for on-market homes includes listing data that provides valuable signals about the home’s eventual sale price. This data isn’t available for off-market homes.

Properties that have been listed for a full year transition to off-market valuations because they have been listed longer than normal for that local market. This can result in a large difference between the list price and the Zestimate.

Updates to your home facts are factored into the Zestimate. However, if the updates are not significant enough to affect the home’s value (eg: paint colors), your Zestimate may not change. Zestimates for all homes update multiple times per week, but on rare occasions this schedule is interrupted by algorithmic changes or new analytical features.

The Zestimate is based on complex and proprietary algorithms that can incorporate millions of data points. The algorithms determine the approximate added value that an additional bedroom or bathroom contributes, though the amount of the change depends on many factors, including local market trends, location and other home facts.

No. The Zestimate is not an appraisal and can’t be used in place of an appraisal. It is a computer-generated estimate of the value of a home today, given the available data.

We encourage buyers, sellers and homeowners to supplement the Zestimate with other research, such as visiting the home, getting a professional appraisal of the home, or requesting a comparative market analysis (CMA) from a real estate agent.

We generate historical Zestimates for most homes if we have sufficient data to do so.

We occasionally recalculate historical Zestimate values along with major data upgrades or improvements to the algorithm.  These recalculations are based on a variety of considerations and, therefore, not every new algorithm release will get a corresponding update of historical values.

However, we never allow future information to influence a historical Zestimate (for example, a sale in 2019 could not influence a 2018 Zestimate). Historical Zestimates only use information known prior to the date of that Zestimate.

Yes — Zillow’s team of researchers and engineers work every day to make the Zestimate more accurate. Since Zillow’s founding in 2006, we have deployed multiple major Zestimate algorithm updates and other incremental improvements are consistently released between major upgrades.

We refresh Zestimates for all homes multiple times per week, but on rare occasions this schedule is interrupted by algorithmic changes or new analytical features.

No. The Zestimate is intended to provide an estimate of the price that a home would fetch if sold for its full value, where the sale isn’t for partial ownership of the property or between family members. Our extensive analysis of foreclosure resale transactions supports the conclusion that these sales are generally made at substantial discounts compared to non-foreclosure sales. For this reason, the Zestimate does not incorporate data about these sales.

The Zestimate is an automated valuation model calculated by a software process. It’s not possible to manually alter the Zestimate for a specific property.

Yes. The Zestimate’s accuracy depends on the amount of data we have for the home. Public records can be outdated or lag behind what homeowners and real estate agents know about a property, so it’s best to update your home facts and fix any incorrect or incomplete information — this will help make your Zestimate as accurate as possible.

You can also add info about the architectural style, roof type, heat source, building amenities and more. Remember: updating home information doesn’t guarantee an increase in the value of Zestimate, but will increase the Zestimate’s accuracy.

We do not delete Zestimates. However, for some homes we may not have enough data to provide a home valuation that meets our standards for accuracy. In these instances, we do not publish the Zestimate until more data can be obtained.

The Zestimate is designed to be a neutral estimate of the fair market value of a home, based on publicly available and user-submitted data. For this purpose, it is important that the Zestimate is based on information about all homes (e.g., beds, baths, square footage, lot size, tax assessment, prior sale price) and that the algorithm itself is consistently applied to all homes in a similar manner.

Zestimates rely on much more than comparable sales in a given area. The home’s physical attributes, historical information and on-market data all factor into the final calculation. The more we know about homes in an area (including your home), the better the Zestimate.

Our models can find neighborhoods similar to yours and use sales in those areas to extrapolate trends in your housing market. Our estimating method differs from that of a comparative market analysis completed by a real estate agent. We use data from a geographical area that is much larger than your neighborhood — up to the size of a county — to help calculate the Zestimate. Though there may not be any recent sales in your neighborhood, even a few sales in the area allow us to extrapolate trends in the local housing market.

The Zestimate was created to give customers more information about homes and the housing market. It is intended to provide user-friendly data to promote transparent real estate markets and allow people to make more informed decisions — it should not be used to drive up the price of a home. Zestimates are designed to track the market, not drive it.

No. The Zestimate is an automated value model and not an appraisal. Most lending professionals and institutions will only use professional appraisals when making loan-related decisions.

If you see two Zestimates for the same property, please let us know by visiting the Zillow Help Center and selecting Submit a request. You may see more than one Zestimate for your address if you are a homeowner with multiple parcels of land. Zillow matches the parcels on record with the county. If you officially combine parcels, the county will send us updated information.

While the Zestimate is the estimated market value for an individual home, the Estimated Sale Range describes the range in which a sale price is predicted to fall, including low and high estimated values. For example, a Zestimate may be $260,503, while the Estimated Sale Range is $226,638 to $307,394. This range can vary for different homes and regions. A wider range generally indicates a more uncertain Zestimate, which might be the result of unique home factors or less data available for the region or that particular home. It’s important to consider the size of the Estimated Sale Range because it offers important context about the Zestimate’s anticipated accuracy.

Millions of consumers visit Zillow every month. When combined with the guidance of real estate professionals, the Zestimate can help consumers make more informed financial decisions about their homes.

Real estate professionals can also help their clients claim their home on Zillow, update the home facts and account for any work they have done on the property. A home’s Zillow listing is often the first impression for prospective buyers, and accurate information helps attract interest.