Christmas lights calculator
Enter your tree’s height and how full you like the lights. You’ll get the number of lights, strands to buy and the cost to run them.
Lights needed
700 lights
- Strands to buy
- 7 100-light strands
- Power draw
- 42 watts
- Cost for the season
- $1.36
- Cost per day
- $0.05
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How it works
The usual rule of thumb is about 100 mini lights for every foot of tree height. Use 50 per foot for a softer look, and 150 or more if you like a tree that glows. The calculator multiplies height by your choice and rounds strands up.
Running cost uses typical wattages: about 6 watts per 100 LED mini lights and about 40 watts per 100 incandescent ones. Check the box for your exact sets.
Example
With tree height 7 ft, look: classic: 100 lights per foot, lights per strand 100, bulb type: lED mini lights (about 6 W per 100), hours lit per day 6 hours, days lit this season 30 days, electricity rate 0.18 $/kWh, the answer is 700 lights.
Tips before you buy
- Wrap from the trunk out to the branch tips and back, a section at a time, rather than circling the outside of the tree. It looks fuller and uses the lights more evenly.
- Check the box for how many sets you can connect end to end. Incandescent mini lights often allow only a few, LED sets many more.
- Use outdoor-rated lights and cords outside, and a plug-in timer so they’re not on all night.
- Test every strand before it goes on the tree.
Common questions
How many lights do I need for a 7 foot tree?
About 700 for a classic look, so seven 100-light strands. Use 350 for a light touch or 1,050 for a full, bright tree.
How much does it cost to run Christmas tree lights?
Very little with LEDs. 700 LED mini lights for 6 hours a day for 30 days cost about $1.36 at $0.18 per kWh. The same number of incandescent lights cost about $9.07.
How many lights for a 6 foot tree?
About 600 for a classic look, or six 100-light strands.