Christmas lights calculator
Enter your tree’s height and how full you like the lights. You’ll get the number of lights, strings to buy and the cost to run them.
Measuring in feet and inches? Use the US version
Lights needed
594 lights
- Strings to buy
- 6 100-light strings
- Power draw
- 36 watts
- Cost for the season
- 1.6 in your currency
How it works
The usual rule of thumb is about 100 lights for every foot of tree, which is about 330 per metre. Use half that for a softer look, or 500 per metre for a tree that glows. The calculator multiplies height by your choice and rounds strings up.
Running cost uses typical wattages: about 6 W per 100 LED lights and about 40 W per 100 old-style filament bulbs. Check the box for your exact set.
Example
With tree height 1.8 m, look: classic: about 330 lights per metre, lights per string 100, bulb type: lED (about 6 W per 100), hours lit per day 6 hours, days lit this season 30 days, price per kWh 0.25, the answer is 594 lights.
Tips before you buy
- Wrap from the trunk out to the branch tips and back, a section at a time. It looks fuller than circling the outside.
- Use lights and leads rated for outdoor use outside, and a plug-in timer so they’re not on all night.
- Test every string before it goes on the tree.
Common questions
How many lights do I need for a 6 ft (1.8 m) tree?
About 600 for a classic look, so six 100-light strings.
How many lights for a 7 ft (2.1 m) tree?
About 700 for a classic look, or seven 100-light strings.
How much does it cost to run Christmas tree lights?
Very little with LEDs. 600 LED lights for 6 hours a day for 30 days use about 6.5 kWh, so about £1.62 at 25p per kWh.