Square Footage - Net or Gross - Clarification- Co-ops or apartment buildings

[Saul L.]

Hi all,

I was wondering if anybody can give me a qualified answer to the following:

When searching on internet data bases- (for example Zillow, Trulia, Street Easy and others) their is usually a square footage given for the unit.

The question is regarding co-ops or multi family units,- is this figure net or gross. ?

In other words, does it include shared/public areas such as lobbies, stairwells, storage etc. (Gross) or is it the actual floor space of the living unit (Net)

If its the net area- is there any way to clarify the gross area ? (or vice versa)

Perhaps an accepted ratio ?

All educated answers or insights greatly appreciated.