The Colosseum could hold approximately 50,000 spectators. Modern estimates vary, but this figure is a standard rounded estimate and remains a fair answer for a general-knowledge quiz.
The amphitheatre’s seating was arranged in steep, socially ranked tiers. The emperor and senior officials occupied the best positions near the arena, while senators, equites, ordinary citizens, women, enslaved people, and the poor were assigned different sections. Seating organization reflected the hierarchy of Roman society.
The building was designed to move enormous crowds efficiently. It had about 80 ground-level entrances, numbered access routes, stairways, and passageways called vomitoria. These did not cause vomiting; the Latin term referred to the rapid discharge of crowds from the building.
Some ancient and modern estimates are higher. The Codex-Calendar of 354 gave a capacity of 87,000, while later scholarship has proposed figures ranging roughly from 50,000 to 80,000 depending on the period and assumptions about seating. Thus, 50,000 is not an exact permanent limit, but it is the conventional approximate answer.