TradeCalculator.co.uk
Socket Spacing Calculator — UK Socket Layout Guidance
Plan socket-outlet layouts with recommended quantities and mounting positions, based on NHBC Standards, Electrical Safety First / Scottish Technical Handbook Table H7, Approved Document M and BS 7671.
Longest internal dimension of the room (metres)
Shortest internal dimension of the room (metres)
Multiplier on the rule-of-thumb sockets-per-m² rate; 1.0 = standard. The NHBC/ESF Table H7 minimum always applies regardless.
Raise the minimum outlet count (0 = use the room-type / Table H7 default). Cannot drop below the authoritative minimum.
Safety notice
Electrical work in dwellings can be notifiable under Part P of the Building Regulations. Treat these figures as planning guidance only: circuits must be designed, installed and certified to BS 7671 by a competent person, normally a registered electrician.
Next up: related pages
How We Calculate This
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.
Frequently Asked Questions
A kitchen typically needs a minimum of 8 socket outlets, with more for larger kitchens. Plan sockets above the worktop (150mm above surface height) for small appliances like kettles, toasters, and food processors. You also need dedicated circuits for the oven, hob, fridge-freezer, and dishwasher. Keep sockets at least 300mm from the sink.
In NEW dwellings, Approved Document M (para 1.18, Diagram 1.5) requires wall-mounted socket-outlets to be between 450mm and 1200mm from the finished floor level, so all habitable-room sockets should sit within that band — 450mm is the usual practical height. Kitchen worktop sockets sit 150mm above the worktop surface (typically about 1050mm from floor) and garage/workshop sockets are often at 1100mm. The older 300mm height is the legacy pre-2010 convention and is now only used when altering existing properties, not for new builds.
Standard 13A socket-outlets must be at least 2.5m horizontally from the boundary of Zone 1 (BS 7671 Reg 701.512.3), which in most bathrooms means just outside the room. The exceptions allowed inside are a shaver supply unit to BS EN 61558-2-5 (with isolating transformer), which may be sited in Zone 2 or outside the zones where direct shower spray is unlikely, and a SELV socket-outlet. Note that Zone 3 was removed in the 17th Edition of BS 7671 (BS 7671:2008), so the correct term is now 'outside the zones'. All bathroom circuits must have 30mA RCD protection.
Zone 0 is inside the bath or shower tray. Zone 1 is directly above Zone 0 to a height of 2.25m from floor level. Zone 2 extends 0.6m horizontally from Zone 1. Beyond that is simply ‘outside the zones’ — the old Zone 3 was removed in the 17th Edition (BS 7671:2008); the 17th and 18th Editions both have only Zones 0, 1 and 2. Each zone has strict rules about what electrical equipment and IP rating is permitted. These are defined in BS 7671 Section 701. Use our Bathroom Zone Calculator for detailed zone layout guidance.
Approved Document P (electrical safety in dwellings) sets no minimum socket count — it only governs the safety, competence and notification of electrical work. The recognised minimum-provision figures come from NHBC Standards 8.1.6 for new homes (8 outlets each in the kitchen and main living room, 6 in the main bedroom, 4 in other bedrooms) and from Electrical Safety First’s ‘Minimum provision of socket-outlets in the home’ guidance, reproduced as Table H7 of the Scottish Technical Handbook (Standard 4.6), which bands twin-socket counts by floor area. Too few sockets lead to extension-lead use, a known fire risk, so this calculator applies those minimums. Once you know how many sockets you need, use our Circuit Breaker Sizing Calculator to determine the correct MCB rating for the circuit.
Was this calculator helpful?
Last updated: February 2026
Verified against UK standards · estimates only, confirm with your supplier.