It’s a common complaint.  You go to an open house or a showing and the listing agent gives you a show sheet with approximate square footage.  You look around.  She must be mistaken.  The listing says 800 square feet, and you estimate about 650.

Is the agent lying?

Most likely, not.  No one would lie.  The agent would lose his or her license if it came back to haunt them. 

Some of the time, the agent gets the square footage information from the seller (if the agent is lazy).  That’s a mistake.

The agent might go as far as pulling the public record - to see if there is a unit deed and plan on file.  Any recent conversion will have a record on the Suffolk Deeds website.

The City of Boston has this information on their website, as well.

Some estimates of square footage take the exterior dimensions of a building - so if a building’s lot is 20 feet x 34 feet, then the unit must be 680 square feet.  This disregards such things as common areas (stairs, mechanicals, etc.).

A more practical measurement is of the interior, livable space.

To some, arguing about square footage is a waste of time.  A condo is a condo is a condo - if it’s too small or too big for you, what difference does it make about square footage?

Curbed.com discussed the issue, today:

Could you please address the very problematic issue of measuring square footage? I’ve been looking to purchase a one-bedroom in Manhattan for awhile, and the square footage is usually greatly overstated, as you probably know well. How can realtors get away with advertising 800 square feet, when the simple calculation of floor plan space will often yield 500, for example?

Interesting fact I didn’t know, however:

Actually, the correct methodology to measure coops and condos is using the interior perimeter methodology adopted by Fannie Mae for mortgage appraisals and gross building area for buildings. The interior perimeter method is from inside wall to inside wall, including all interior walls, closets halls and baths. It excludes all common areas.

This, courtesy of Jonathan Miller, appraiser extraordinaire.

Bring a tape measure next time you go to look at a condo.