Christmas lights running cost calculator (UK)
See what your Christmas lights cost per hour, per day and for the whole season. It starts at the Ofgem price cap rate of 26.32p per kWh (1 October to 31 December 2026), and you can change every number.
Quick answer: a 5W LED string on for 6 hours a day costs about 0.8p a day and 29p from 1 December to 6 January. Older 40W bulbs cost about £2.34 over the same time.
How we calculate this
The formula
kWh per day = watts x sets x hours / 1000. Cost per day = kWh per day x rate. Season = cost per day x days.
Worked example
Three 20W LED sets on for 8 hours a day use 20 x 3 x 8 / 1000 = 0.48 kWh a day. At 26.32p per kWh that is about 12.63p a day, or £4.67 over 37 days.
Assumptions
- Unit rate starts at 26.32p per kWh, the Ofgem price cap average for 1 October to 31 December 2026. Change it to match your bill.
- The daily standing charge is not included, because it does not change with use.
- Preset wattages are typical figures. Check the plug or box.
- A guide, not a quote.
Developers and AI tools can run the same maths as JSON: topmagpie.com/api/v1/tools/christmas-lights?type=led-500&sets=3&h=8&d=37
What Christmas lights cost to run
At 26.32p per kWh, 6 hours a day. These are typical wattages, so check your own set.
| Lights | Per hour | Per day | 37 days |
|---|---|---|---|
| LED string, about 100 bulbs (5W) | 0.1p | 0.8p | 29p |
| LED string, about 500 bulbs (20W) | 0.5p | 3.2p | £1.17 |
| LED net or curtain lights (25W) | 0.7p | 3.9p | £1.46 |
| Large outdoor LED display (50W) | 1.3p | 7.9p | £2.92 |
| Older non-LED mini bulbs, 100 bulbs (40W) | 1.1p | 6.3p | £2.34 |
| Light-up inflatable with fan (100W) | 2.6p | 16p | £5.84 |
How it's worked out
Watts per set × number of sets × hours per day ÷ 1,000 gives the kWh used each day. Multiply by your unit rate for the daily cost, and by the number of days for the season.
Preset wattages are typical figures for each type of light, not tested readings. LED sets vary a lot, so use the number on your plug or box. Standing charges are not included.
Rate source: Ofgem energy price cap, average Direct Debit electricity unit rate (England, Scotland and Wales), 1 October to 31 December 2026.
Common questions
How much do Christmas lights cost to run in the UK?
Very little if they are LED. A 5W set of 100 LED bulbs on for 6 hours a day costs about 0.8p a day, or 29p from 1 December to 6 January, at 26.32p per kWh.
How much do LED Christmas lights cost per hour?
A 5W LED string costs about 0.1p an hour and a 20W set about 0.5p an hour at 26.32p per kWh.
Are old Christmas lights more expensive to run?
Yes. A 40W set of older non-LED mini bulbs uses about eight times the power of a 5W LED set, so about £2.34 over the season at 6 hours a day, compared with 29p.
How do I find the wattage of my Christmas lights?
Look on the plug, transformer or box for a number followed by W. If it shows volts and amps, multiply them together. An energy monitor plug will show the exact figure.
Is it cheaper to use battery or solar Christmas lights?
Solar lights cost nothing to run but can be dim in a UK December. Battery lights cost more in batteries than mains LEDs cost in electricity, unless you use rechargeables.
Do light-up inflatables use a lot of electricity?
More than lights, because a fan runs all the time. At about 100W, one on for 6 hours a day costs about 16p a day, or £5.84 over the season.
Should I leave Christmas lights on overnight?
It is safer and cheaper not to. Use a plug-in timer or smart plug to switch them off at bedtime, and never leave old or damaged sets on unattended.
What rate does the calculator use?
It starts at the Ofgem price cap average Direct Debit unit rate of 26.32p per kWh (1 October to 31 December 2026). Change it to match your bill. Standing charges are not included.
Are cheap Christmas lights safe?
Buy from a known seller, look for the UKCA or CE mark, check the cable and plug each year, and use outdoor-rated lights and sockets outside.
What else costs money to run at Christmas?
Cooking and heating cost far more than lights. Try our appliance running cost calculator and heater running cost calculator.