1) Legal minimums vs. real project

The legal side: RD 486/1997 sets 2 m² of free floor area per person, 10 m³ of free volume and, for offices, a minimum height of 2.5 m. It also specifies a 1.0 m minimum corridor width and 0.80 m for external doors. Use this as a red line to avoid non-compliance.

The practical side: the “useable area per workstation” is larger than those minimums because it includes furniture, manoeuvring and circulation. In open plan, many offices use reference densities of 5–8 m²/workstation for the workstation zone alone, to which common areas (meeting rooms, kitchen, reception) are added. Tip: calculate the workstations first, then add rooms and support spaces according to use.

To validate the minimum free area, rely on the INSST tool. For design, use the quick rule below and check that aisles respect the 1-metre minimum.

2) Common desk sizes and their impact

The most common tops per workstation range from 120×60 cm to 160×80 cm; the larger the top (or the more peripherals and storage), the more m² you will need per workstation.

• Compact (≈120×60): high density, good for small teams or hot-desking.
• Standard (≈140×70): balance of space and cost.
• Comfort (≈160×80): better for large monitors or intensive work.

Reference desk dimensions used in the market (ranges 120–160 cm wide and 60–80 cm deep).

3) Quick rule in 3 steps

1. Usable work area (UA): take the m² of the zone where workstations go (excluding toilets, cores, enclosed rooms). If you only have the total, approximate UA as 60–70% of the total (depends on the site and programme).
2. Reserve for circulation (aisles between rows, access): subtract 25–35% of UA (adjust by how many aisles you have and remember the legal minimum of 1.0 m width).
3. Divide by m² per workstation: use 5.5–6.5 m²/workstation for standard setups (140×70 or 160×80 desk with chair and manoeuvre space).
   Formula: workstations ≈ (UA × (1 - circulation_factor)) ÷ m2_per_workstation

Important: this rule is a practical estimate, not a regulation. Always verify compliance with RD 486/1997 (free area/volume, minimum widths) before signing off the plan.

4) Density templates (choose yours)

Remember: aisles must be at least 1.0 m wide, and external doors at least 0.80 m (minimums in RD 486/1997).

5) Worked examples

Example A: unit with 100 m² total

• Estimate UA (workstation zone) ≈ 65% ⇒ 65 m².
• Reserve circulation 30% ⇒ 65 × 0.70 = 45.5 m² net.
• Use 6 m²/workstation ⇒ 45.5 ÷ 6 ≈ 7–8 workstations.

Example B: 250 m² floor with rooms already set

• After rooms/toilets/reception you have UA = 140 m² for workstations.
• Circulation 28% ⇒ 140 × 0.72 = 100.8 m² net.
• m²/workstation 5.5 ⇒ 100.8 ÷ 5.5 ≈ 18 workstations.

Minimum legal checks

• With 18 people, minimum total free area required: 18 × 2 = 36 m² (well covered by 100.8 m² net).
• Office height: ≥ 2.5 m; free volume: ≥ 10 m³/person.
• Main aisles: ≥ 1.0 m wide; external doors ≥ 0.80 m.

6) Frequently asked questions (FAQ)

Is “2 m² per person” enough to size workstations?

No. It’s a legal minimum of free area, excluding furniture and circulation. For design, use m²/workstation and a circulation factor, then validate the RD 486/1997 minimums.

What corridor widths should I allow?

At least 1.0 m, and external doors of 0.80 m. These are minimums, not comfort recommendations.

Which desk sizes work best?

Depends on usage. Common market sizes are 120×60, 140×70 and 160×80 cm. The larger the desk and equipment, the higher the m²/workstation.

Is there an official tool to validate free area?

Yes. The INSST provides a calculator for the minimum free area per worker (useful as a final check).

7) Useful links on FactoryOficina

• Refurbished office tables
• New office tables
• Refurbished office chairs
• New office chairs
• Refurbished storage
• New storage
• More guides on our blog