calculating the square 'footage' of the room [=calculating the size of the room in square feet]
Some disturbing 'footage' of the war was shown on the evening news.
(..) Nancy! Is she okay? It's okay, I got you. Did you get that? Yeah. I'll have the footage developed and get it over to Father Gordon. He's our liaison at the church. I imagine we'll get a pretty fast response. - Listen, Roger? - Yeah? (..)2013 The Conjuring
(..) I don't want you girls going down there. - That place is loaded with spiders. - Ew! Just relax. Okay. Stop it, Nancy. It's not funny. We've got extra square footage anyway. I'll check it out in the morning. - I wonder why it was boarded up. - I don't know. Okay, show's over. - Five minutes. (..)2013 The Conjuring