For businesses sizing a new office
Office Space Calculator: How Much Space You Need
Sviatoslav JerdetchiiCEO & Founder of Craftex. Updated , 5 min read
The short answer
To work out how much office space you need, multiply the people in on your busiest day by about 10 m² (108 sq ft) each. Then adjust for your layout, growth and meeting rooms.
- 10 m² per person is the British Council for Offices design standard for general workspace.
- Open plan needs less per person; cellular offices need far more.
- Size for the busiest day over the lease, not today's average.
- Test-fit the building before you sign: the drawing shows the real number.
An office space calculator starts with one number: the people in on your busiest day. Multiply them by about 10 m² (108 sq ft) each, the British Council for Offices standard. Then adjust for your layout, your growth and the rooms you need.
This page gives you the rules, a lookup table and a worked example for 50 people. The numbers come from the UK design standard, the legal minimum and our own plans of ten layouts on one floor.
A calculator gets you to a range. The real answer comes from drawing your team on the actual floor, and that is what our space planning team does before you sign. Looking at buildings now? Book a free design consultation and send us the floor plans.
Office space calculator: the quick rule
Use three steps to size an office.
- Count the people in on your busiest day, including the growth you expect over the lease.
- Multiply by 10 m² each, or about 108 sq ft. That is the design standard for general workspace.
- Adjust for your layout: less for dense open plan, more for private rooms and cellular offices.
| People | Open plan, 8.6 m² | UK standard, 10 m² | Hybrid, 11.6 m² |
|---|---|---|---|
| 10 | 86 m² (926 sq ft) | 100 m² (1,076 sq ft) | 116 m² (1,249 sq ft) |
| 20 | 172 m² (1,851 sq ft) | 200 m² (2,153 sq ft) | 232 m² (2,497 sq ft) |
| 30 | 258 m² (2,777 sq ft) | 300 m² (3,229 sq ft) | 348 m² (3,746 sq ft) |
| 50 | 430 m² (4,629 sq ft) | 500 m² (5,382 sq ft) | 580 m² (6,243 sq ft) |
| 75 | 645 m² (6,943 sq ft) | 750 m² (8,073 sq ft) | 870 m² (9,365 sq ft) |
| 100 | 860 m² (9,257 sq ft) | 1,000 m² (10,764 sq ft) | 1,160 m² (12,486 sq ft) |
The 10 m² column is the British Council for Offices standard. The other two come from our own drawings of an open plan and a hybrid office on the same 720 m² floor, core included.
Square feet per person by office layout
The layout changes the answer more than anything else. We drew ten layouts on one 36 × 20 m floor and counted the desks. Here is the floor area each desk takes, core included.
| Layout | Desks | m² per desk | sq ft per desk |
|---|---|---|---|
| Benching | 128 | 5.6 | 60 |
| Open plan | 84 | 8.6 | 93 |
| Private offices plus open desks | 78 | 9.2 | 99 |
| Hybrid | 62 | 11.6 | 125 |
| Screened workstations | 50 | 14.4 | 155 |
| Team clusters | 48 | 15.0 | 161 |
| Cellular | 16 | 45.0 | 484 |
Benching sits well below the 10 m² standard. The British Council for Offices now treats 8 m² as a special case, so very dense plans need a good reason. Cellular offices take five times the floor of open plan per person.
Every layout is drawn in our guide to the main types of office layout.
The legal minimum is a floor, not a target
HSE guidance says a workroom needs at least 11 cubic metres per person when empty, counted up to 3 m high. That is about 3.7 m² of floor with a 3 m ceiling, or 4.6 m² with a 2.4 m one.
HSE adds that this may not be enough once furniture fills the room. It doesn't apply to meeting rooms. No office should be sized from it.
Allow for growth and hybrid days
Size the office for the lease, not for this month. A five-year lease signed for today's team is often too small by year three.
Hybrid working cuts the other way. If nobody is in every day, you may not need a desk for every person. The British Council for Offices says designing for 10 m² per person gives room for the mix of settings hybrid teams use.
- Growth: add the headcount you expect by the middle of the lease.
- Busiest day: count who is in on your peak day, not the weekly average.
- Desk sharing: fewer desks than people only works with booking rules and lockers.
- Visitors: clients and interview candidates need somewhere to sit.
Add meeting and support space
Desks are only part of the floor. Meeting rooms, phone booths, the kitchen, breakout space, storage and print all need room, and corridors join them up.
On our hybrid drawing, the meeting and support rooms take about 201 m² of the 720 m² floor. They are two meeting rooms, a board room, phone booths, a focus room, the kitchen and breakout. That is just over a quarter. Teams that meet a lot, or host clients, need more.
- Meeting rooms: count how many meetings run at once on your busiest day.
- Phone booths: more people on calls means more small rooms.
- Kitchen and breakout: the place people choose to come in for.
- Storage and print: less than it used to be, but rarely zero.
I can honestly say our office has been completely transformed thanks to Craftex. From the very first meeting, the team was approachable, professional, and full of creative ideas that really made sense for our business. They didn’t just focus on how the space would look but also how it would work for the team day-to-day. The new layout is efficient, modern, and welcoming, and you can tell they really thought about the details. The whole process was smooth and surprisingly stress-free. They kept me updated at every stage, which gave me confidence. I’m really happy with the results and wouldn’t hesitate to recommend them to anyone.
A worked example for 50 people
Say you have 50 staff today and expect 60 within three years. Your busiest day brings in about four in five people.
- Plan for growth: 60 people by the middle of the lease.
- Busiest day: four in five of 60 is 48 people in.
- Apply the standard: 48 × 10 m² = 480 m², about 5,167 sq ft.
- Split it: just over a quarter, about 134 m², goes to meeting and support space. The rest holds the desks and routes.
- Check the layout: a hybrid at 11.6 m² per desk would need about 557 m² for 48 people. A dense open plan would fit in less.
So a business like this should look at floors of roughly 480 to 560 m², about 5,200 to 6,000 sq ft. Then test the shortlist.
When to test-fit a building
A calculator gives you a range. A test fit tells you whether a particular floor works.
Columns, a deep floor, few windows or an awkward core can cost you desks. Two floors of the same quoted area can hold very different numbers of people.
Test-fit before you sign heads of terms, while you can still walk away. Ask the agent for the floor plans and the landlord's fit-out guide. Then draw your brief on each building you are considering.
- Two or three buildings: test them side by side.
- The landlord's rules: what you can change, and when noisy work can happen.
- The Cat A or shell condition: what the landlord hands over decides what you build.
Our guide to office space planning covers the five steps from brief to layout. When the floor is chosen, see how we fit out offices in London.
From a number to a floor plan
The calculator answers "roughly how big". A drawing answers "will we fit, and how will it work". Do both before you commit to a lease.
Send us the floor plans you are looking at and your headcount. We draw the test fit, show the desk and room numbers for each building and tell you what the fit-out will need. Book a free design consultation and we'll come back the same working day.
