Garden Lighting Calculator — Lights, Cable & Cost

Path lights should be spaced 1.5-3 metres apart depending on their brightness and spread. Closer spacing (1.5-2m) gives more even light; wider spacing (2.5-3m) creates pools of light for a more dramatic effect. Stagger lights on alternate sides for the best look.

Add up the total wattage of all lights and choose a transformer rated at least 20% higher. For example, 10 lights at 3W each = 30W, so use a 40W or 60W transformer. This headroom allows for cable voltage drop and future additions.

Mains LED lights are brighter, more reliable, and last longer. Solar lights require no wiring but are dimmer, weather-dependent, and batteries need replacing every 1-2 years. Mains is best for paths and security; solar works for decorative accent lighting.

LED garden lights are very cheap to run. The exact cost depends on the number of fittings, their wattage and your tariff: a typical 15-20 light scheme totalling 30-50W and running 5 hours a night costs roughly £5-£20 a year at a 28p/kWh electricity rate (for example, 39W × 5 hours × 365 nights × £0.28 = about £20). Lower-wattage decorative fittings sit at the bottom of that range. Solar lights cost nothing to run but have higher upfront costs and shorter lifespans.

Most low-voltage garden lights use 12V systems with 1.5mm² two-core outdoor cable. Runs over 20 metres may need 2.5mm² cable to reduce voltage drop. Always use cable rated for direct burial or run it through conduit.