How accurate are Zillow estimates?

I’m constantly asked how accurate are Zillow estimates, known as ‘Zestimates’, and I can’t tell you how many times I’ve heard a seller tell me ‘but Zillow says my home is worth more/less.

For some reason, people have come to treat Zestimates as the defacto standard. Maybe it has something to do with our desire for instant gratification. In today’s internet-obsessed society, we want instant answers.

How accurate are they? Not very. They are better used as a starting point for determining value, not the endpoint.

According to Zillow’s own statistics (, Boston/Suffolk  is one of their more accurate areas and they say their accuracy is 5.3% of the sales price.

So, let’s think about that. For a $400,000 condo, 5% is $20,000, which means their Zestimate could be anywhere from $380,000 to $420,000. If you are the seller of that condo, you would see that as a pretty big price difference.

For Boston, Zillow also says 25.6% of their estimates are off by more than 10%. For that same $400,000 condo, 10% is $40,000. So, 25.6% of their estimates would be under $360,000 or over $440,000.

However, sometimes the Zestimates are right on the money. People see the ones that are very accurate and are impressed – ‘Wow, they really got that one right. This tool is pretty good.’ The inaccurate ones are rationalized away – ‘Well, it’s just an automated tool and some of the data it is using is probably incomplete or wrong’.

It’s fun to check the values on Zillow, but just remember it is just a starting point.

The problem with Zestimates and other AVM’s (Automated Valuation Model) is there are too many qualitative data points to consider that are not part of the model, such as:

  • Hardwood floors throughout.
  • Kitchen remodel you just did.
  • The walls you removed to open up the place up.
  • The energy efficient appliances you installed.
  • The new windows throughout.

and there are a few data points that are more relevant to condos:

  • The floor level. On initial sale of a building, the higher the floor, the higher the price. $5,000 – $10,000 per floor is not uncommon.
  • The side of the building you are. In some buildings, one side faces a busy street and the other side a quiet courtyard.
  • The view. This can be a huge difference maker. In some buildings, one floor you might be looking into a brick wall of another building and the next higher floor has an incredible view of downtown and the monuments.

Because of these numerous, qualitative data points, an automated value model will always be suspect. They are getting better every day, but I’m not sure they will ever get to the same accuracy that a good real estate agent or appraiser can provide.

If you are thinking of selling and need an accurate value of your condo, contact me at

Contact me to set up an appointment to start your Boston condo buying process.

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Author Profile

John Ford
John Ford

Over the course of 20 years in the Boston downtown real estate market, John represented and sold numerous, condominiums, investment and development properties in Greater Boston and in the surrounding suburbs

In addition to representing Boston condo buyers and sellers, John is currently one of the most recognized Boston condo blog writers regarding Boston condominiums and residential real estate markets. John's insights and observations about the Boston condo market have been seen in a wide variety of the most established local & national media outlets including; Banker and Tradesman, Boston Magazine The Boston Globe, The Boston Herald and NewsWeek and Fortune magazine, among others.


For over 24 years, John Ford, of Ford Realty Inc., has been actively involved in the real estate industry. He started his career in commercial real estate with a national firm Spaulding & Slye and quickly realized that he had a passion for residential properties. In 1999, John entered the residential real estate market, and in 2000 John Started his own firm Ford Realty Inc. As a broker, his clients have come to love his fun, vivacious, and friendly attitude. He prides himself on bringing honesty and integrity to the entire home buying and selling process. In addition to helping buyers and sellers, he also works with rental clients. Whether you’re looking to purchase a new Boston condo or rent an apartment, you’ll quickly learn why John has a 97% closing rate.


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John Ford and his staff can be reached at 617-595-3712 or 617-720-5454. Please feel free to stop by John's Boston Beacon Hill office located at 137 Charles Street.

John Ford
Ford Realty Inc
137 Charles Street
Boston, Ma 02114



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