Capacity comes from the building's fire and safety licence, not from how many people would physically fit. It appears in the tech spec and again in the contract.
What it means for the deal
Fee and split are built on it. A €1.500 guarantee against a 400-capacity room at €18 a ticket is a different risk to the same fee in a 900-capacity room. Promoters price a show from capacity, ticket price and expected Sell-through.
Two numbers, not one
Standing and seated capacity differ in the same room, often by half. Production eats into it as well: a wide stage, a front of house position and a barrier can take 50 places out of a club. Ask which figure the contract is using.
Where to check it
The venue's tech spec states the licensed number. The ticketing capacity sits a few percent below it, because production holds and guest list come off the top before anything goes on sale.