Part B · England · Free to use
Occupancy and means of escape calculator
Occupant capacity from floor space factors, then number of exits, exit widths and travel distance by purpose group.
Approved Document B Volume 2 (2026 PDF)
Your inputs
Results update as you type.
Exclude stairs, lifts, WCs and fixed structure (Appendix D, D2).
Part B · Result
140 occupants
2 exits needed, each at least 1,050 mm wide.
Checks passed- Occupant capacity: Calculated result140 m² ÷ 1 m² per person140 people
- Number of exits: Checks passedmin 2 (Table 2.2)2
- People through each remaining exit: Calculated resultlargest exit discounted (para 2.21)140
- Exit width: Checks passedmin 1,050 mm (Table 2.3)1,050 mm
- Travel distance: Checks passedmax 45 m, purpose group 5, more than one direction32 m
- Assumes exits of equal width; with mixed widths, add the capacities of the remaining exits (para 2.22).
- Stairs must be at least as wide as any storey exit onto them. Use the stair capacity calculator for upper floors.
Clauses this relies on
Source edition and scope
Approved Document B Volume 2 (2026 PDF).
Assumes equal exit widths. Confirm the use, escape strategy and any additional fire safety conditions before relying on the result.
This is a preliminary check of the conditions shown. Confirm the edition, project circumstances and any additional requirements with your architect or building control.
A design aid, not legal advice. Checked against the Building Regulations 2010 for England; confirm with building control.