Event capacity: occupant density, exit widths and escape time

For a standing audience at an open-air event in England, an event capacity calculation starts at 0.3 m² a person: divide the ground people can actually stand on by 0.3 and you have the official fire guidance's maximum operating capacity for that area, on density alone. That is half the answer. The other half is how many people your exits can clear in the escape time, and the lower figure counts.

In short:

• Standing crowd: 0.3 m² a person in England's open-air fire guidance (about 3.3 per m²). It is a design figure, not a physical limit.
• Scottish Government fire guidance gives a load factor of 0.5 m² for an open-air standing spectator area, and says it does not set capacity limits on its own.
• Deduct stages, bars, stalls and structures before you divide.
• Exit width = people ÷ (rate of passage × escape time), with the widest exit lost.
• The result feeds a fire risk assessment. It is not a licence.

What an event capacity figure is, and what it is not

A figure from area and exit width is an input to the fire risk assessment, not an agreed number. The documents behind it carry different weight:

• Statute. In England and Wales the Regulatory Reform (Fire Safety) Order 2005 requires the responsible person to carry out a fire risk assessment, enforced in most premises by the fire and rescue authority. In Scotland the duties sit in Part 3 of the Fire (Scotland) Act 2005 and its 2006 regulations.
• Official guidance. Fire safety risk assessment: open-air events and venues (February 2007) was published under Article 50 of the Order to help responsible persons meet their duties. Its gov.uk page, now held by the Home Office, lists it as applying to England. The figures below come from it. The guide says it is written for less complex open-air events and does not cover large temporary structures or air-supported structures; more complex sites will probably need assessing by someone with comprehensive fire risk assessment training or experience.
• Sports grounds guidance. The Guide to Safety at Sports Grounds (the Green Guide), from the Sports Grounds Safety Authority (SGSA), is written for sports grounds; its rates of passage are the more cautious published pair.
• Industry guidance. The Purple Guide, from the Events Industry Forum, has a crowd management chapter with a section on safety capacity limits. It is a subscription publication, so nothing from it is reproduced here; see our Purple Guide explainer.

Whatever the area gives, the open-air guide says the permitted capacity "should never exceed the capacity of the available escape routes".

Occupant density: the figures in the gov.uk guide

Table 3 of the guide (printed page 66) gives typical occupant densities, in square metres a person:

• Standing spectator or audience area, or an unseated bar: 0.3 m²
• Assembly area, dance floor or hall: 0.5 m²
• Dining area, seated bar or restaurant: 1.0 m²
• Skating rink, sports area or sales area: 2.0 m²
• Display gallery or workshop: 5.0 m²
• Camping area: 6.0 m²
• Car park: two people for each parking space

Where numbers are not otherwise known, such as at unticketed events, the guide finds a maximum operating capacity as occupied area ÷ occupant density; a ticketed event starts from the tickets. Either way it counts everyone there at any one time: public, staff and contractors.

How many people per square metre at a festival?

At 0.3 m² a person, a standing audience works out at about 3.3 people per square metre; at 0.5 m², 2 per square metre. The Scottish Government's Practical fire safety guidance for existing non-residential premises (February 2022) puts an open-air standing spectator area at 0.5 m². It adds that occupancy capacity is not used to set capacity limits, because it takes no account of means of escape. Neither figure is a density to aim for.

Event capacity calculation, step by step

1. Measure each separate area on its own: the arena, a bar marquee, a dance tent.
2. Take out the ground people cannot use: the guide names stalls and temporary structures, which usually means the stage and pit, mix position and bars.
3. Divide what is left by the density for its use.
4. Check the result against your exits, which can cut it.

Exit widths and rates of passage

For open-air areas the guide works from the escape time and the capacity of the routes: total exit width = people ÷ (rate of passage × escape time). Measure each route at its narrowest clear point, whether a gate, a gap between concessions or guy ropes.

Rates of passage

• gov.uk open-air guide: 109 people per metre per minute on routes in standing and other areas. The figure is 73 in seated accommodation and on stairways.
• Green Guide, as the SGSA summarises it: 82 on a level surface and 66 on a stepped one. The SGSA calls these maximum rates; designing a level route to less than 82 gives more comfortable circulation.

The gap matters: the same exits clear about a quarter fewer people at 82 than at 109.

Escape time

Table 4 ties the escape time to the fire-risk level: not more than 5 minutes at higher risk, up to 10 minutes at lower risk, with normal risk between. Most outdoor areas of typical events are likely to be normal; an enclosed concert site where movement is restricted for security might be higher.

Number and width of exits

• Assume the widest exit is lost to fire and size the rest without it. Where two exits are close enough for one fire to affect both, you may need to discount both.
• The guide's own open-air worked example uses exits at least 1.05 m wide, and keeps at least two in use once the largest is discounted.

Exits from marquees and temporary structures

The guide gives a second method under its indoor escape routes, for marquees and temporary structures; open-air areas use the flow formula above.

• No exit narrower than 1.05 m. One exit serves at most 60 people. Above that, at least two, far enough apart that one fire is unlikely to affect both.
• An exit of at least 1.05 m takes up to 160, 200 or 240 people at higher, normal or lower risk. Allow 75 mm more for each further 15 people, or part of 15.

Travel distances

The guide uses travel distance for indoor situations; open-air areas are judged on escape time and exit capacity instead. Inside marquees, tents and other temporary enclosures, it sets a travel distance to the nearest exit (Table 5, printed page 70), walked around tables, chairs, stalls and equipment:

• Marquee or tent: 18 m with more than one escape route, 6.5 m with only one.
• Other temporary enclosure, more than one route: 25 m, 45 m or 60 m at higher, normal or lower fire risk.
• Other temporary enclosure, single route: 12 m, 18 m or 25 m.

The guide calls these suggested distances, which can move with the level of risk. It lists a crowded beer tent among places where the risk may be higher, and asks you to consider shorter distances there.

The fire risk assessment is the basis

Every figure above rests on a judgement:

• the risk level picks the escape time, the exit-width row and the travel-distance column;
• the usable area depends on what you deduct;
• the rate of passage is a choice between two published pairs.

They are for the responsible person, with a competent person's help where in doubt, as the guide advises. HSE adds that capacity is often limited by emergency exits and audience circulation.

Where there is a premises licence, the section 182 licensing guidance (September 2026, para 2.18) describes a permitted capacity: a limit on people on the premises at any time, following a recommendation by the fire and rescue authority. A Safety Advisory Group (SAG) advises on the plan. HSE says a SAG has no legal powers and cannot approve or prohibit an event, and the organiser keeps the legal duties. See event site plans and the SAG.

Worked example: a fenced concert arena

A concert arena in a field is fenced at 100 m × 60 m, so 6,000 m² gross. Inside it, the stage and pit take 900 m², the mix position 100 m², and the bars and food stalls 400 m². That leaves 4,600 m² of standing ground.

• At 0.3 m² a person: 4,600 ÷ 0.3 = 15,333 people, the maximum operating capacity on density alone.
• For comparison only, the Scottish load factor of 0.5 m² gives 4,600 ÷ 0.5 = 9,200: a load-factor figure, not a capacity.

The organiser plans 8,500 tickets plus up to 300 staff, traders and contractors at peak: 8,800 people, well under the area figure, so the exits decide.

The arena has four 4 m gates, leaving 12 m once the widest is lost. The assessment rates the arena normal risk, with an 8-minute escape time:

• At 109: 12 × 109 × 8 = 10,464 people, enough for 8,800.
• At 82: 12 × 82 × 8 = 7,872 people, 928 short.

A fifth 4 m gate gives 16 m with the widest lost: 16 × 82 × 8 = 10,496 people.

If the assessment rates the enclosed arena higher risk, the escape time falls to 5 minutes and 8,800 people need 8,800 ÷ (82 × 5) = 21.5 m of exit with the widest lost: six 4 m gates in use plus one to lose, seven in all.

Nobody has agreed a capacity here. The example shows why the area rarely binds, and why the risk level and rate basis should be recorded with reasons.

Headcounts that other regimes use

• Temporary Event Notice (England and Wales): a TEN covers at most 499 people at any one time, counting the staff running the event.
• Martyn's Law: under the Terrorism (Protection of Premises) Act 2025, an event can qualify where 800 or more people, staff included, may reasonably be expected at the same time (other conditions apply, including entry checks). As at 20 October 2026 the duties are not in force: legislation.gov.uk shows section 3 as prospective, and the Home Office factsheet (updated 24 July 2026) expects an implementation period of at least 24 months from Royal Assent on 3 April 2025. See Martyn's Law for events.

How Airship Event Designer works it out

In Airship Event Designer, the Events mode of Airship Site Designer, an Arena zone's label shows its area and its capacity at 0.3 m² a person, and a Campsite zone uses 6 m² a camper, both from Table 3. The capacity comes from the whole area you draw: the app does not subtract the stage, bars or other structures inside it, so deduct their footprint yourself when you read the label. You can draw the edge to leave out a stage at one end, but keep it on the gates, because a gate counts as an exit only where its centre lies within 2 m of the zone's edge (our own tolerance).

The checks discount the widest gate on each crowd zone's edge and judge the rest on the rate of passage you choose (82 or 109) and an escape time held between 5 and 10 minutes. They look for exits of at least 1.05 m, and two or more above 60 people. As our own reading, they also walk travel distances round the structures in each crowd zone and set them against Table 5's figures for other temporary enclosures; the guide itself sets Table 5 for indoor situations, not open-air areas.

Every finding names its basis: the source and page where a figure is published, or ours where it is not. None of it is a capacity decision. See the event checks and zones and their capacities. Event Designer is in beta on Pro and above, switched on per account: see what it does.

Questions organisers ask

How do you calculate event capacity?

Divide the usable area by the occupant density, then check that your exits, with the widest lost, can clear that many people in the escape time. The lower figure governs.

How many people per square metre is a festival crowd?

England's open-air fire guidance uses 0.3 m² a person for a standing audience, about 3.3 people per square metre. That is a design figure for an assessment, not a target or a physical limit.

Do staff count towards event capacity?

Yes: the gov.uk guide counts everyone present at any one time, and the TEN limit (England and Wales) and the Martyn's Law threshold both include staff.

Is there a festival capacity calculator?

The arithmetic fits on a spreadsheet; the inputs that matter (usable area, risk level, escape time, rate of passage) are judgements for the responsible person, with a competent person's help where in doubt.

Who sets the final capacity of an event?

The responsible person works it out in the fire risk assessment, and the fire and rescue authority enforces the Fire Safety Order. A licensing authority may set a capacity condition. A SAG advises but cannot approve.

Sources

• Fire safety risk assessment: open-air events and venues, HM Government, 2007
• Egress, Sports Grounds Safety Authority
• Practical fire safety guidance for existing non-residential premises, Scottish Government, 2022
• Section 182 guidance, Licensing Act 2003, Home Office, September 2026
• Safety Advisory Groups and Venue and site design, HSE
• Temporary Events Notice (England and Wales), GOV.UK
• Terrorism (Protection of Premises) Act 2025, section 3, legislation.gov.uk
• Martyn's Law overarching factsheet, Home Office, updated 24 July 2026
• Crowd Management, The Purple Guide, Events Industry Forum (subscription)

Last reviewed 20 October 2026.

These figures start the responsible person's assessment, with a competent person's help where in doubt; what the event holds is settled by the duty-holders with the fire and rescue and licensing authorities, on the SAG's advice. This is general information, not legal advice.