There are a few reasons for this. The first and foremost reason square footage is listed as a range is the liability to the agent inputting the information. Along with this fact, sometimes you will also see a statement in the comment section of the MLS listing that states "BUYERS AGENT TO VERIFY SQUARE FOOTAGE". With that said, the agent does not want to be liable for the square footage being less that published.

The second reason is that no one really knows for sure exactly what the square footage is. The square footage of any home can and does differ from one appraisal to another. It's just the way the appraiser calculates it.

Another reason for this range is simply for a search criteria for the agent to input wants and needs in to the MLS system to locate properties for a perspective buyer.