What is the capacity of a school?

A recent NY Times article describes the unusual way in which charter schools are welcomed by the city, and share space in public school buildings: City’s Schools Share Their Space, and Bitterness .

The bitterness in the headline has to do with the fact that it can be difficult to agree on how much space is available in a school, i.e. what is its capacity.

"Officials estimate that over all, the city’s schools are 80 percent full. But figures vary widely school to school, with some bursting while others have as many as a dozen classrooms not being used for teaching. Even determining how many rooms are free is contentious — most schools use open space for activities like dance, tutoring and computers — but Education Department officials often treat those rooms as “underutilized space” to allow another school to come in. "