Zillow, Trulia and Redfin are great tools; however, they are using AVM's (automated valuation models). They are not taking factors into account such as quality, condition, etc. In New England, we have such a mixture of property types. We may have a colonial, next to a ranch, next to a cape and then some commercial influence mixed in. The estimates provided by these services cannot be deemed 100% accurate. The places where those values work well are in TX, CA, FL, etc. that are larger states with homogenous neighborhoods where the only difference is one home has a one car garage, and the second home has a 2 car garage. If your value matches the value posted by one of these websites it would be by coincidence only. We urge our customers to use these sites as tools and for information only, please do not rely on the values that are listed as they may or may not be accurate.