Socket Spacing Calculator — UK Socket Layout Guidance

This calculator uses room type and dimensions to recommend socket-outlet quantities and positions. Minimum outlet counts come from NHBC Standards 8.1.6 and the Electrical Safety First / Scottish Technical Handbook (Standard 4.6, Table H7) area bands; mounting heights come from Approved Document M; bathroom rules come from BS 7671 Section 701. Approved Document P does not set socket numbers, spacing or heights — it only governs the safety and notification of the work itself.

How we calculate

We start from a sensible-density rule of thumb (room area × a sockets-per-m² factor, which you can scale with the density factor) and then apply a floor: the result is never allowed to fall below the NHBC room minimum or the ESF/Scottish Table H7 count for the room’s floor-area band. The higher figure is used. Suggested spacing divides the room perimeter by the number of socket positions, assuming double sockets.

The per-m² density factor is an unofficial best-practice rule of thumb, not a published standard. The binding numbers are the NHBC and ESF/Table H7 minimums.

Room-type recommendations

• Kitchen: NHBC minimum 8 outlets (Table H7: 6/8/10 twins by area), at least 3 left free. Worktop sockets 150mm above the surface.
• Living room: NHBC minimum 8 outlets (Table H7: 4/6/8 twins by area), plus 2 near the TV point. Part M height 450–1200mm.
• Bedroom: NHBC main bedroom 6 / other bedrooms 4 (Table H7 double bedroom: 3/4/5 twins). Part M height 450–1200mm.
• Bathroom: Shaver supply unit (BS EN 61558-2-5) or SELV outlet only inside; standard 13A sockets ≥2.5m from the Zone 1 boundary.
• Garage: Minimum 4 (Table H7: 2/3/4 twins). Workshop height around 1100mm.
• Home office: Minimum 6 (Table H7 study: 4/5/6 twins). Part M height 450–1200mm, or desk height.

Table H7 bands twin-socket counts by floor area (up to 12m² / 12–25m² / over 25m²); each twin counts as two outlets. Modern homes with more devices usually benefit from extra sockets — it is always cheaper to install more during construction than to add them later.