Work out egress width instantly with clear inputs, formula shown and shareable results.
Egress width is the occupant load multiplied by a capacity factor, conventionally 5 mm per person for level travel and 8 mm for stairs, divided between the available exits and never less than the code minimum clear width. Codes also require the remaining exits to serve the full load if the largest is discounted.
Egress width
Total mm = occupants x width per person; per exit = total / exits, not less than the minimum
Redundancy
Check total / (exits - 1) with the largest exit discounted
Preliminary estimate only. Means of escape must be designed to the fire and building code adopted locally and verified by a qualified fire engineer.
Total mm = occupants x width per person; per exit = total / exits, not less than the minimum. Egress width is the occupant load multiplied by a capacity factor, conventionally 5 mm per person for level travel and 8 mm for stairs, divided between the available exits and never less than the code minimum clear width.
People move more slowly and less densely on stairs, so the same flow rate needs more width. That is why stair capacity factors are roughly 60 percent higher than for level routes.
This calculator takes 4 inputs: Occupant load, Width per occupant, Number of exits, Minimum clear width per exit. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.