Zillow is a billion-dollar Internet marketer that "gives" "z-estimates" that claim to calculate the sales value of each and every property in the United States. Zillow tries to achieve this this feat by using a fancy algorithm which compares factors which affect property values, but here's a typical story I have heard from real estate sellers in Northern Virginia:

Our home was recently appraised for 650K. Zillow estimates the value at 521K. The estimate makes us one of the lowest priced homes in the subdivision. We have all upgrades in our home and it is the largest of the homes that were originally built in this subdivision. It was appraised at 750K before 2009. Our home has a basement. Neighbors do not have basement on one side and you appraised higher. Really? -- James E. - Fort Hunt

If you search the Internet for the phrase "Can I trust Zillow?" or "Can I trust Z-Estimates" you'll discover many posts by upset property owners and skeptical property buyers who have discovered the hard way just out inaccurate Zillow's pricing can be. Many people in Potomac_ridge say that Zillow's estimates have a margin of error of around 20%. Even if we assume the margin of error is only 10%, in Northern Virginia that means a "z-estimate" is only within $50,000 of the actual value. If the margin of error is an improbable 5% that means that a z-estimate is only within $25,000 of the asking price.

Yet Zillow (for now) remains popular with some people. Property owners and home shoppers should understand that there is not a single neighborhood in Potomac_ridge where either a bank or tax collector uses Zillow for tax assessment or appraisals. Our expert advice is to take "valuations" from any website at arm’s length. Putting too much reliance into a website can cause a great deal of irration.

Connect with one of our agents today for a free comparative market analysis of your property's worth. We promise that a website won't set the market value. Rather, your friendly neighborhood Nesbitt Realty real estate agent will measure the unique variables which make up your real estate's market value.