HesapHanem

Christmas Tree Lights Calculator

Find out how many lights and 100-light strings your Christmas tree needs for full coverage.

How it is calculated

Enter the tree height in centimetres and the number of lights you want per foot of height. If the per-foot field is empty or zero, the tool uses 100. It converts the height to feet and multiplies:

feet = height ÷ 30.48

lights = round( feet × lights per foot )

strings = ceil( lights ÷ 100 )

The light count is rounded to the nearest whole light. The string count assumes strings of 100 lights and is always rounded up, since you cannot buy part of a string. Height must be above zero. The tool measures height only, not the width or fullness of the tree, so a wide tree needs more than a slim one of the same height. Lower per-foot values give a sparser look and higher ones a denser look.

Worked example

A tree 240 cm tall, using the default of 100 lights per foot:

  1. Height in feet: 240 ÷ 30.48 = 7.874 ft.
  2. Lights: 7.874 × 100 = 787.4, rounded to 787.
  3. Strings of 100: 787 ÷ 100 = 7.87, rounded up to 8.

You need 787 lights, which means buying 8 strings. That gives 800 lights in total, so you will have 13 lights of spare capacity. At 150 lights per foot the same tree needs 1,181 lights, or 12 strings.

Try this example →

Common mistakes

  • Typing the height in feet or metres. The field is in centimetres, so a 7 ft tree must be entered as about 213 and a 2.4 m tree as 240. Entering 7 gives 23 lights.
  • Forgetting that the result is based on height alone. A 240 cm tree with wide branches needs more lights than a slim one, so raise the per-foot value for wide trees.
  • Buying exactly the light count in strings of a different size. The string count assumes 100-light strings; if your strings hold 50 or 200, divide the light count by that number yourself.
  • Ignoring the cord between lights. Strings differ in spacing, and a 100-light string may be shorter or longer than the branch run it has to cover.
  • Not checking how many strings can be connected end to end. The count tells you how many to buy, not how many a single outlet or plug can support.

About this calculator

The standard rule professional tree decorators use is about 100 mini-lights per vertical foot (roughly 330 lights per meter) of tree height for full, evenly lit coverage, which scales up for a fuller, more layered look and can be halved for a sparser, minimalist style — the calculation simply multiplies tree height by this per-foot rate and then divides by 100 to find how many standard 100-light strings are needed.

This ratio comes from how professional Christmas tree lighting and retail display decorators plan large trees, since it accounts for wrapping lights not just around the outer surface but also into the tree's interior branches for depth, which is what separates a professionally lit tree from a sparse-looking one.

Home decorators buying lights before setting up their tree, event planners lighting large displays in malls or town squares, and holiday decorating businesses quoting jobs by tree size all use this rule of thumb to estimate exactly how many strings to buy or bring.

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  • Editorial team

    The count depends on height alone, so a wide tree needs more than a slim one of the same height; raise the lights per foot for a fuller tree. Before buying, read the packaging for how many strings may be joined end to end on one plug, since that limit is separate from the light count. How many lights per foot look right on your tree?

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