How accurate is Zillow?

I bought my house 3 years ago. I started tracking it on Zillow just last year, and it looks like it’s starting to creep back to its pre-housing crisis status (meaning a tidy little profit for me). But I have absolutely no faith in this website, its estimate, etc. - my house is only worth what someone else will pay for it. And with at least three other houses on my street for sale (some for over a year), that seems like a long shot at best at the moment (even in this so-called “stable” historical district).

To be fair, I’m not sure how something like this could really be all that accurate, and it uses all the information pretty well. For example, when I found the website, it had my house listed as having 2.0 baths when it is actually 1.5. I changed that bit of info, and the next month’s estimate dropped the price down a couple thousand.

According to my real-estate agent friend, not very. She says we could realisticsally sell our house for almost 40% more than its Zestimate. Zillow obviously does not account for any upgrades you’ve made to your house unless you manually add it, and even then I don’t know that it gets a very accurate appraisal.

I just refinanced my home last month. The company that facilitated my refinance used Zillow as their initial bases for a valuation of my home. As I continued through the process with them, we ultimately got to the point where I had to have a physical appraisal. The appraiser’s report, which I received approximately 1 week later, valued my home $44,000 more than Zillow. Not a huge difference, but higher all the same.

The above stated, I think it would be a mistake to discount the importance of Zillow in determining the value of a home as the industry does use it as a reference.

I would say using zillow is a SWG. It has my house under the other houses in Neighbor hood. The other houses are small one storries, mine is a 2 story. And we have a lot about 60% bigger. And I have added onto the house twice. So I would guess that they are off by maybe as much as $150,000.

Before I bought my parent’s house, we had it appraised. The estimates between our appraiser, the mortgage bank’s appraiser (both of whom showed up to our house), and Zillow were all within a couple thousand dollars. It was surprisingly accurate in our case. Of course, you win some, you lose some, but I’ve had good luck with Zillow, and think most people way overestimate the value of their homes, and Zillow is pretty good at giving you an idea of who’s in the right ballpark.

Note also that Zillow gives you a range in the estimate, which may be tighter or looser based on how much data is available in the neighborhood you’re looking in.

I’ve seen Zillow be all over the map. Sometimes pretty accurate, sometimes wildly off.

It doesn’t even show my father-in-law’s house in Chicago. No listing for it at all, although it does have listings for other houses in the same neighborhood. I have no idea why.

My father-in-law’s house is on the market and has been for over a year; Zillow says it’s not for sale.

There’s a house less than a block away for sale. Zillow lists it at nearly 50% more than our house. Same superficial specs: sq. ft., bedrooms, baths, etc. Except that we have a huge basement, they have none, larger garage, etc. I think one thing that’s different about ours is that we appealed our property tax assessment a while back and they didn’t. So the county thinks theirs is worth more. That and what the Realtor has set for a listing price. (Which is something of a joke. A sad joke on the poor owners who are going to end up selling it for less than they paid for minus $10s of thousands of improvements.)

All too often, prices set by Realtors determine prices for houses that have been recently listed, even if they don’t sell.

I don’t put much stock in it.

I own an investment townhouse, and it’s virtually a commodity - there are a lot of other almost identical units in that development and in similar developments in the immediate vicinity. So the price can be known with a lot of confidence within a 5% range. Zillow’s estimate is way off (and has changed dramatically over the last year, a time period in which prices have not moved much).

One thing in particular that I suspect Zillow is not up on is short sales and foreclosures, and on phony prices listed for houses, and these influence their estimates.

OTOH, I just filed for a refinancing and the agent said upfront that Zillow says it’s worth such-and-such. But I’m guessing the agents are used to people’s estimates of their houses worth being even more off-base than Zillow’s. We’ll see what the appraiser thinks.

The answer almost certainly is ‘it depends’. I’ve bought and sold a number of houses in California and I have found it to be both eerily accurate and completely laughable. I would use it as one data point out if many, and don’t put too much faith in it.

My older house in Apple Valley, CA:

Zillow Estimate: $316k
In Escrow ATM for: $440k

39% more than Zillow, who doesn’t even know it’s for sale, but then I had it only on the market for about 45 days.

A few years ago I worked for Zillow on the Zestimate algorithm. In discussions we had inside and outside the company I’ve decided this:

If the information Zillow has on your house is accurate then their Zestimate is just as likely to be “accurate” as any other source. I put “accurate” in quotes because, as someone said up-thread, the worth of your house is what someone else will pay for it. If you’re lucky enough to get two parties bidding on your house then it will be “worth” more. If other comparable houses are for sale in the area then your house is worth less until they sell.

Keep in mind that real estate agents aren’t any better at gauging the worth of your home. Their estimate will be the highest price that they think will sell quickly. If you sell it yourself you’ll likely get a higher closing price (assuming you’re willing to wait a few weeks to sell).

This may have changed since I was there, but Zillow doesn’t know a house is for sale unless someone posts it on the site. The real estate industry generally doesn’t share information about what’s for sale (for free, anyway).

I doubt it.

A local guy who understands the area is always going to be more acurate than some computer algorithm. There are a lot of houses that are superficially similar in many ways but local people or people who deal in local real estate can tell you off the bat that the values are different.

[In addition, even if Zillow’s info on your house is accurate, the info on the comps that it uses might not be.]

In my area, if you search on recently sold properties, they almost always sell for 5-10% less than the Zillow estimate. Could be a regional thing; I would interested what people in other parts of the country find when they search on sold properties.

My daughter is in the process of refinancing her home, and her appraisal came in yesterday. Zillow has the house at $142,000 and the appraisal was $149,000.

Let’s not forget that Zillow has some pretty large error bars, if you look at the high/low of their estimate. For my house, that’s +/- 25%.

I use Zillow frequently in my tax work when I need a quick & dirty (and documentable) source for fair market value on properties. In my area of Washington, the values are pretty much right on for properties without improvements (provided that Zillow’s basic data on the house is correct). If you’ve done wainscoting and granite countertops, the Zestimate is definitely going to be low.

If you polled all real estate agents in the area and asked them for a price for each house they would generally be off by 5-10% as well. (If you believe Freakonomics then they would, on average, undersell your property by at least that much.)

But only if the local people know what’s in all the houses, and they likely don’t. Zillow probably knows more about the houses that aren’t for sale than the local agents, so it tends to balance out.