Required exit count is a step function, not a gradient. You get one exit up to 50 occupants. Then two up to 500. The cliff at 500 is steep — one more occupant doubles your exit requirement. This tool makes the cliff visible.
Purpose: the IBC exit thresholds are unintuitive until you see them as bands. Orange marks where you are. The cliff at 500 is the one that surprises architects.
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Occupant load
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Required exits
Position within IBC band
1
≤ 50
exit
2
51–500
exits
3
501–1,000
exits
4+
> 1,000
exits