Some of Zillow's own stats on the accuracy of its Zestimates. As you can see, the margin for error ranges from as low as 4.8% in D.C. to a whopping 10% in San Francisco.

Are Zillow’s “Zestimates” Full Of Zhit? Depends Who You Ask

If you’ve looked at real estate in the last few years, you’ve almost certainly reviewed the listings on Zillow.com and you’re probably quite familiar with the “Zestimate,” the site’s automated approximation of what the property is worth. Some realtors say Zestimates are useless and cause confusion for their customers, while Zillow defends the data. Interestingly, both sides use the same stats to argue their case. [More]