Home Search

Find out how much your Home is worth!

The Zestimate (pronounced ZEST-ti-met, rhymes with estimate) home valuation is an estimated market value, computed using a proprietary formula. We plunked a Z in front of the word "estimate" to show it is the result of our calculations — and because it's our favorite letter of the alphabet.

How do we come up with the Zestimate?

We compute this figure by taking zillions of data points — much of this data is public — and entering them into a formula. This formula is built using what our statisticians call "a proprietary algorithm" — big words for "secret formula." Currently, we calculate a Zestimate for more than 48 million homes. We are adding data all the time and in the coming months we expect to add Zestimates for many more homes in the U.S.

What's in this formula?

One eye of newt … Actually, it's less wizardry than mathematics. When our statisticians developed the model to determine home values, they explored how homes in certain areas were similar (i.e., number of bedrooms and baths, and a myriad of other details) and then looked at the relationships between actual sale prices and those home details. These relationships form a pattern, and they used that pattern to develop a model to come up with a market value for a home.

Is that all there is to it?

That's oversimplifying something that is incredibly robust and sophisticated, but it's the basics. Hundreds of home details feed into the formula and the home characteristics are given different weights according to their influence in a given geography and over a specific period of time. And, because the details are always changing, the Zestimate is extremely timely — it indicates the value of a home based on the most recent data available in an area. We receive new data and update the Zestimate regularly to capture new sales in a neighborhood. However, there is a delay between when the county is notified of a transaction and when we find out about it. We might not know for some time about the sale of that house down the street from you that happened last week.

Why do I see home values for the past?

We not only have Zestimates for homes now, we have used massive computing cycles to go back in time to generate historic Zestimates as well. Sound hard? It is, but it's critical because it allows you to see how a home (or an area) has appreciated in value over the years. You can see a home's appreciation in a chart that looks just like a stock table. Your home is, after all, a major asset in your overall portfolio.

My Zestimate is too low — or too high. What gives?

The Zestimate is really a starting point in figuring out the true value of a house. A variety of things can affect the accuracy of the Zestimate. For example, the number of transactions in a geographic area affects how much we know about prevailing market values of homes there. The more transactions, the more data and the more accurate the Zestimate will be. Also, we use public data for house attributes, and some areas report more data than others. The more attributes we know about homes in an area (including yours), the better the Zestimate. To correct for this, we offer a tool called My Estimator that allows you to adjust the Zestimate according to specifics about a home.

How accurate is it overall?

Our data shows that the majority of our Zestimate home valuations are within 10% of the selling price of the home. Of course, to a certain extent this depends on the accuracy of the home data we receive; see our Data Coverage and Zestimate Accuracy table. (You can refine the Zestimate using the "My Estimator" tool, adding things you may know about but we don't, such as remodeling information.) When it comes to unique homes (e.g., luxury mansions, unusual designs) we are less accurate in our Zestimates.

Who calculates the Zestimate and how do they do it?

We don't have homing pigeons flying from land parcel to land parcel to come up with the Zestimate for a house, but we DO have statisticians who work all day — and some nights — with a huge amount of data. They live and breathe valuation models and tweak algorithms to get us closer to actual market value.

What's the Value Range?

The Value Range (the numbers below your Zestimate) shows how much we know about your home. The bigger the range, the less data went into developing your Zestimate and the less certain we are about the worth of the home. The smaller the range, the more accurate the Zestimate because we have lots of information to go on.

But you don't know about my granite kitchen counter and my river view!

It's true, we've never been to your house, never seen your expertise with colors and landscaping. Only you know those things. So we've given you a way to consider them in calculating a home's value with the My Estimator tool. Enter an address for any home, then click on "Create an Estimate." My Estimator will walk you through the steps to adjust your valuation.

Is a Zestimate an appraisal?

The Zestimate is not an appraisal and you won't be able to use it in place of an appraisal, though you can certainly share it with real estate professionals. It is an estimate of the worth of a house today, given the data we have available. Zillow.com does not offer the Zestimate as the basis of any specific real-estate-related financial transaction. Our data sources may be incomplete or incorrect; also, we have not physically inspected a specific home. Remember, the Zestimate is a starting point and does not consider all the market intricacies that can determine the actual price a house will sell for, such as entertaining offers, negotiating, closing costs, timing, etc.

Can I use the Zestimate to get a loan?

No, you can't. To get a federally guaranteed loan, a law called FIRREA (the Federal Institutions Reform, Recovery and Enforcement Act) requires an appraisal from a professional appraiser. The Zestimate is our estimate of fair market value, a starting point for home buyers and sellers and anyone just plain interested in the value of houses. You can use it in negotiating, in judging market trends, and in calculating all sorts of things for your personal purposes. But, if you needed a loan or help in understanding the ins and outs of financing, please visit our Finance section.

Where does all the data come from? How can you know all this stuff?

The data — believe it or not — is public. What? You've never seen it? That's because it is hard to find and hidden in multiple sources. We've done the legwork for you by getting huge amounts of data from many sources and creating something unique that the public sources don't provide — a Zestimate of your home based on the public data.

Utah Real Estate and Utah Home Search!