UPDATE: Zillow greatly improved the accuracy of their Zestimates in June 2016 so I updated this post in July 2016. Post was originally published in July 2015.
Note: I haven't updated the video to reflect Zillow's improved accuracy.
You have a home for sale and Zillow's Zestimate for the house...
Zillow publishes the median percentage error of their Zestimates but I think it's a lot easier to think in dollars rather than in percentages. So I converted the published Zestimate percentage errors into dollar errors for 25 U.S. metro areas and the U.S. as a whole.