What is a social distancing capacity calculator?

3 min read
Sep 10, 2020

The Covid-19 pandemic and the social distancing guidelines that followed have caused a problem for place and facilities managers of office buildings and public spaces. You might know the total capacity of your building in normal times, but what about when you need to ensure the health and safety of staff and customers?

This is where a social distancing capacity calculator comes in.

These tools will help determine the number of people you can have in the building at any one time and still adhere to social distancing guidelines. Whether you’re responsible for a corporate workplace, educational institution, restaurant or leisure facility, in this blog we’re going to look at how they work.


How to measure and calculate room capacity and allow for social distancing

Current UK Government advice (and majority of Governments around the world) is that people should remain at least one metre apart, but there has been no other information released to help businesses understand what they need to do in terms of occupancy limits.

With this in mind, the Institute of Place Management has laid out some guidance on the issue of capacity planning based on various distances.

The calculations involved aren’t as simple as you might think. As IPM explains, for two people to maintain a distance of 2 metres, they both need a space of 1 metre around them. There’s a simple calculation to then work out how much space each person needs to keep two metres apart:

𝛑r² = 3.14m² per person

If your building has a total floor space of 100m², then you could admit 31.84 people to maintain that distance. However, this only works in theory. As soon as one person moved, every other person in the building would have to move by the same distance to maintain 2 metres from everyone else. The same problem applies for 1.5 metre and 1 metre distances.

This works fine in queuing scenarios where everyone is static and moves together, but in this case the 3.14m² figure isn’t quite right. When you place the circles together there is some wasted space that also has to be considered - see below:

Circles in a square (2)

The actual required space for this situation is 3.99m².

The above is referred to as ‘square packing’, but for environments where people are moving around, the IPM used hexagonal packing for their calculation.

To solve the issue of movement, they added a second circle around each person, an additional metre from the inner circle.

IPM1Credit: Institute of Place Management

The inner circle is where the person can move around, but how big does that need to be? IPM simply used the average walking speed (1.46m/s) and determined how far someone would walk in one second, which is 0.73m.

Finally, to work out the total space required per person, the calculation was:

3.14(0.73+1)²/0.9069m² = 10.36m²


Social distancing requirement Space required per person
  1 metre   10.36m²
  1.5 metres   16.11m²
  2 metres   25.8m²


To calculate your building or rooms maximum occupancy, simply divide the total area of that space by the space required per person.

What to do when you know the occupancy limit

Once you’ve calculated the total capacity of your building, how do you monitor it effectively? You could have a member of staff simply count people in and out, but this is far from a perfect solution and will likely lead to counting errors and great expense.

An occupancy sensor with a high degree of accuracy solves this problem. The Irisys SafeCount solution anonymously counts people as they enter and exit a building with a 99.5% accuracy, even if you have multiple entrances and exits. The system can then provide visual warnings and alerts when limits are approached or exceeded.

To find out more about how SafeCount works and how occupancy monitoring can help you adhere to social distancing guidelines click below. Alternatively, request a demo here.

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