How Much Office Space Do We Need? UK Calculator 2026
Updated 5 May 2026
Hybrid formula: Headcount × 60% × 10 m² + experience layer
BCO 2024 baseline. 60% peak attendance + 10 sqm NIA per occupied desk + 30-40% overhead for meetings and breakout.
10 staff
80-120 m²
50 staff
400-600 m²
100 staff
800-1,200 m²
All figures are NIA — Here’s Why That Matters
All office sizing calculations in this guide use NIA (Net Internal Area) — the usable floor area excluding lift cores, toilets, plant rooms and internal walls. This is what office leases quote and what BCO density studies measure. When you view a property, GIA (Gross Internal Area) is typically 15-25% larger than NIA. A 1,000 sqm GIA office typically has 750-850 sqm NIA. Always confirm which measure an agent is quoting.
The Hybrid Formula (BCO-Aligned)
Required NIA (sqm) =
Headcount × Peak occupancy % × Space per occupant (sqm)
+ Meeting rooms (15-25 sqm each, 1 per 8-12 staff)
+ Breakout / kitchen (15-20 sqm per 10-12 staff)
+ Focus pods, phone booths, wellness room
+ Growth buffer (10-20% of total)
The right question in 2024-2026 is no longer “how many desks?” It is “how much space does the work need on its busiest day, and what experience does it need to deliver?” (JLL, BCO). The BCO 2024 guidance sets a 66% utilisation benchmark — down from 80% in 2019 — formally recognising that hybrid working has permanently reduced peak attendance. For most UK SMEs, planning for 60% of headcount on the busiest day is conservative and appropriate.
The experience layer — meeting rooms, breakout, focus zones, phone booths, wellness room — typically accounts for 30-40% of total NIA in a modern hybrid fit-out. Under-provisioning this is the most common mistake: if all meeting rooms are booked by 10am on Tuesdays, the office is not failing because it is too small overall, but because it has too many open desks and too few rooms.
Worked Examples: NIA by Headcount (Hybrid 60% Peak)
All NIA. Space per workstation: 10 sqm. Source: Knight Frank, BCO, Oktra, Pilcher London.
| Headcount | Peak desks (60%) | Workstation NIA | Total NIA | Total sq ft |
|---|---|---|---|---|
| 10 | 6 | 60 sqm | 80-120 sqm | 861-1,292 |
| 25 | 15 | 150 sqm | 210-260 sqm | 2,260-2,799 |
| 50 | 30 | 300 sqm | 400-600 sqm | 4,306-6,458 |
| 100 | 60 | 600 sqm | 800-1200 sqm | 8,611-12,917 |
| 250 | 150 | 1500 sqm | 2000-2800 sqm | 21,528-30,139 |
10-person team
80-120 sqm
A single open-plan room of 80-100 sqm in a Class E office building. One meeting room (1 per 8-10 staff), small kitchen/breakout. Consider a private office suite in a flex centre at 6-9 sqm/desk — often cheaper than a direct lease for under 15 people.
25-person team
210-260 sqm
Half a floor or a whole floor of a smaller office building. Two meeting rooms, a kitchen/breakout, a reception area. Consider a 250 sqm NIA lease or a larger private office in a coworking centre.
50-person team
400-600 sqm
A full floor in most mid-market UK office buildings. Four meeting rooms minimum, two focus pods, a substantial breakout kitchen and a reception/collaboration zone. Pre-pandemic, 50 staff occupied c. 600-700 sqm — hybrid saves one full meeting room’s worth.
100-person team
800-1200 sqm
One or two floors. Eight meeting rooms, four focus rooms, two phone-booth clusters, generous breakout and a bookable collaboration zone. The 800 sqm end suits tech-dense, trust-high hybrid; 1,200 sqm suits professional services with client meeting requirements.
250-person team
2000-2800 sqm
Three to four floors or a small standalone building. Town planning-scale decision. Requires a dedicated facilities team; consider managed flex to avoid long-lease risk at this size.
Attendance Policy Adjustments
The worked examples above assume a 60% peak (free hybrid). Adjust the peak multiplier for other attendance policies.
| Attendance policy | Peak multiplier | sqm/FTE result | Desk ratio |
|---|---|---|---|
| Full-attendance (5 days) | 1.0× | 10-12 sqm | 1:1 desk-to-FTE |
| Anchor-day hybrid (2-3 fixed days) | 0.7-0.8× | 7-9.6 sqm | 0.8:1 |
| Free hybrid (50-60% target) | 0.6× | 6 sqm workstation | 0.7:1 |
| Remote-first with hub | 0.3× | 3.6 sqm workstation | 0.3:1 |
Pre-Pandemic Comparison
In 2019, the same 100-person team would have been planned at 1.0× headcount × 12 sqm NIA = 1,200 sqm, plus experience layer, totalling c. 1,400-1,600 sqm. At hybrid 60% in 2026, the total falls to 800-1,200 sqm — a reduction of 25-43% at the same comfort standard. This structural contraction in leased space demand is the defining feature of the UK office market in the 2020s, and the reason average space per occupied workstation has risen from 9.6 sqm (2018) to c. 12.5 sqm (2024) even as total NIA leased has fallen.
Use Class: All Offices Are Class E(g)(i)
Since 1 September 2020, all office space in England falls within Class E(g)(i) under the Town and Country Planning (Use Classes) (Amendment) Order 2020. The old B1(a) office class is gone. Class E(g)(i) can switch to other E uses — gym, surgery, retail, cafe — without a planning application, subject to local Article 4 directions. When assessing office space, verify the GIA-to-NIA efficiency ratio: typical offices run 75-85% NIA, meaning a 1,000 sqm GIA lease provides only 750-850 sqm of usable floor area. Always negotiate on NIA when possible.