Guide
How to calculate venue capacity: the five accepted methods
Updated
There is no formula you can apply blind. There are five recognised methods, and the right one depends on what your venue actually has: a fire strategy, a turnstile, a seating plan or a licence.
The five methods
The Home Office published a non-statutory supplementary document alongside the Terrorism (Protection of Premises) Act 2025 guidance setting out methods for assessing the number of individuals expected to be present. It is the clearest official list of the accepted approaches, and it is useful well beyond that Act (gov.uk).
- A. Safe occupancy for fire safety
- The maximum number that can reasonably be accommodated for fire safety purposes. Many venues already hold this figure from their fire strategy or fire risk assessment.
- B. Historic attendance data
- Records of actual numbers at peak times. The document warns that historic data is not always a reliable predictor and must be reviewed regularly.
- C. Fixed seating or fixed standing positions
- Count the seats or standing positions. Its worked example: 450 fixed seats plus 30 staff on duty gives 480.
- D. Tickets and pre-registration
- The maximum number of tickets that can be issued sets an upper limit. Its worked example: 300 presale plus 600 general sale plus 300 staff equals 1,200.
- E. Restrictions
- A maximum attendance or capacity figure attached to an alcohol and entertainment licence can be used directly. Its worked example: a nightclub licensed for 975, plus staff on duty.
A sixth option exists: other means, used with a written justification of why the alternative is appropriate, how the figure was calculated and why it is reasonable.
Staff always get added
The most common error is counting the public only. Where the method chosen does not already include staff, for example ticketing data or fixed seating counts, the staff number has to be added to reach the final figure. Staff means everyone working at the premises, whether employees, contractors or volunteers, full time, part time or shift workers.
The fire safety route in detail
Approved Document B volume 2 gives two ways to fix an occupant number: the maximum the space is designed to hold, or the area of a room or storey divided by a floor space factor from Table D1 (gov.uk). Measure the area including counters and display units, and exclude stair enclosures, lifts, sanitary accommodation and other fixed parts of the building structure. Where a space has more than one type of use, the more onerous factor applies. The factor table on the home page reproduces the full list.
Dwell time changes the answer
Total visitors in a day is not capacity. The Home Office document works an example: a stately home whose records show 850 visitors on a single day, but which assesses hourly counts and average dwell time and concludes the true maximum present at one time is 300. If your venue sells day tickets and people come and go, this calculation is the difference between two tiers.
Whatever method you use, write down which one and why. The regulator can require the responsible person to show how the assessment was carried out.