How much cable do I need?
Work out how much twin-and-earth cable you need by the metre — and the cost — with the calculation shown. Switch the size to compare 1.5mm² (lighting), 2.5mm² (sockets) and 6mm² (cooker/shower).
1 m of cable per m of run.
| 2.5mm² twin & earth cable (sockets/ring) | 2 × 50 m drum | £96 |
- 1Cable run: 60 m
- 2Usage rate: 1 m of cable per m of run
- 3Allowing for waste: 60 × 1 × 1.1 waste = 66 m
- 4Packs: 66 m ÷ 50 per pack = 2 × 50 m drum
- Ring final circuits for sockets. Add ~10% for routing and drops.
- Indicative trade-counter price; confirm with a current supplier quote.
How to estimate cable runs
- 1Pick the cable size
1.5mm² for lighting circuits, 2.5mm² for ring/radial socket circuits, 6mm² (or more) for a cooker or electric shower.
- 2Measure the run
Estimate the length from the consumer unit around the circuit to each point — and remember cable goes up and over, not in a straight line.
- 3Add generously for waste
Allow extra (often 10–20%) for drops, slack and mistakes — running short mid-circuit is a real nuisance, and cable is sold in fixed drums.
- 4Whole rewire
A full house rewire uses a lot of cable across lighting, sockets and dedicated circuits — see the rewire cost guide for the bigger picture.
Estimating cable is about the circuit runs, not the floor area — and it's always worth allowing generously, because cable comes on fixed drums and running short halfway round a ring is the classic mid-rewire hold-up. Sizing itself (which cable for which load) is an electrician's call; this just helps you gauge the quantity and cost.
Cable sizes by circuit (indicative)
| Cable | Typical use | Notes |
|---|---|---|
| 1.5mm² T&E | Lighting circuits | Fewer amps |
| 2.5mm² T&E | Socket ring/radial | Most common |
| 6mm² T&E | Cooker / shower | High-load circuits |
| 10mm²+ | Large loads / long runs | Sized by design |
Cable sizing is a design decision (load, length, protection) — this is a quantity guide, not a substitute for an electrician. Indicative.
Frequently asked questions
How much cable do I need for a rewire?+
It depends on the house size and circuit layout, but a full rewire uses a lot — lighting (1.5mm²), sockets (2.5mm²) and dedicated cooker/shower runs (6mm²+). Estimate each circuit's run, add 10–20% for slack, and see the rewire cost guide.
What size cable for sockets?+
2.5mm² twin-and-earth is standard for domestic socket circuits (ring or radial). Lighting uses 1.5mm²; a cooker or electric shower needs 6mm² or larger. Final sizing depends on the load and run — confirm with an electrician.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.