How is the Zestimate calculated?

"I’m glad you asked! It’s important to understand that a Zestimate home value is neither random nor unchangeable. I also want to make sure you understand that the Zestimate is not an appraisal. The main ingredient in a Zestimate is data and it’s broken down into three categories:

• A home’s physical attributes that Zillow gets from both public and user-submitted data
• Tax assessments and other tax assessor information
• Past sale records for the home itself and nearby or comparable homes

To calculate the Zestimate, Zillow’s data experts run that data through a series of computer processes—an algorithm. The data is continuously analyzed and compared with real home sale prices, so the Zestimate model will change and improve over time, and Zestimates will become more and more accurate."

~Provided from Zillow.com Scripts