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Free tool

Christmas Tree Lights Calculator

Enter your tree height to see how many Christmas lights and strands you need for a light, classic or dazzling look, plus the power use and cost.

How to use the Christmas Tree Lights Calculator

  1. Enter the height of your tree in feet and choose how many lights are on each strand.
  2. Pick a light, classic or dazzling look and LED or incandescent bulbs.
  3. Read the number of lights and strands to buy, and the power use.

How the light count is worked out

The calculator uses a common rule: about 100 mini lights per foot of tree height for a classic, evenly lit tree. Use 50 per foot for a subtle glow and 150 per foot for a dense look. The number of strands is the light count divided by the lights per strand, rounded up.

Power use is a rough average of 0.05 W per LED mini light and 0.4 W per incandescent mini light. The real figure is on the box.

Tips for a tree that looks right

  • Wrap lights around the branches, not only around the outside of the tree, so the glow has depth.
  • Test every strand before you hang it.
  • Leave the plug end at the bottom, near an outlet.
  • Do not overload an outlet. If a strand or the outlet keeps tripping, see Christmas lights that trip the GFCI.
  • If half of a pre-lit tree goes dark, follow the checks for a pre-lit tree with half the lights out.
  • Never leave a tree lit when you go out or go to bed, and keep a real tree watered.

Planning a bigger purchase? See when Black Friday is for sale timing.

Frequently asked questions

How many lights do I need for a 7 foot Christmas tree?

About 700 mini lights for a classic look at 100 per foot, 350 for a light look and about 1,050 for a dense one. With 100-light strands that is 7, 4 or 11 strands.

How many Christmas light strands can I connect together?

It depends on the brand and type. The limit is printed on the box and on the plug. LED sets usually allow many more strands than incandescent ones, so check before you chain them.

Do LED Christmas lights use less electricity?

Yes, a lot less. A string of LED mini lights uses roughly a tenth of the power of an incandescent string, and runs much cooler.

Should I put lights on before or after the tree is up?

Light each section before you stack a big artificial tree if you can. For a real tree, start at the bottom plug end and work upward, then test before you add ornaments.

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