If you notice, the 2 previous answers are from agents in NH & IL. They are not members of your local MLS Board and as such may not be aware that our CMLS reports square footage in a "range" that is automatically determined. Even when a CMLS Realtor enters the exact, measured square footage, our CMLS automatically determines a "range". Therefore the only way for 3rd party sites like Trulia and Zillow to get a square footage single amount is to rely on tax records. If your tax record is incorrect, it will be reflected as incorrect in these sites. That's why it is important for owners to carefully look over their tax bill and records to verify the correct information. If it is not correct, that is what the tax "appeal" process is for. You appeal to the tax board during that process. Often builders when they get the building permit will give a square footage, but then during the build process make adjustments which can increase or decrease the actual finished square footage. Most Realtors in our area know the most accurate information comes from our CMLS and that is what we use when selecting property to show our Buyer Clients.