Christmas Tree Light Calculator

Create the perfectly lit tree this holiday season with our Christmas-tree-light calculator. Calculations within.



Looking to create the perfect dazzling tree this holiday season with evenly spaced lights distributed vertically and horizontally across your tree? Don’t let the prospect be just another thing stressing you out. How many light strings will I need for the perfect sparkling tree? What’s too much? How much is not enough?

Multi-colored, warm white, pure white, winter white, golden glow? That’s actually something you need to figure out yourself; we’re not that good! 

Incandescent, LED, standard lights, mini lights, wide-angle mini lights, large bulbs, battery-operated lights, animated lights, color-changing lights? Again, that’s on you. Although we vote for LEDs as they consume up to 75 percent less energy and last 25 times as long as incandescents, according to the U.S. Department of Energy. Plus, most incandescents will be phased out by August of 2023. 


christmas tree

Image used courtesy of Adobe Stock


Before you begin, you will need two things. First, what is the height of your tree canopy (that's the part of the tree with limbs)? Second, how wide is your tree at the bottom of the canopy? That’s it. 

This simple-to-use calculator will alleviate some of the stress associated with the holidays and, as a result, you’ll be set to sit back and enjoy your Martha Stewart-worthy holiday display. 

Happy holidays!


The Christmas Tree Lighting Calculations

For you engineers whose Christmas wish is to know how we are performing these calculations, we've got your present right here. This is the equation we are using to calculate the total conical helical arc length for the lighting that we will need.

$$L_{total} = \frac{(4H^2+D^2) \cdot asinh(\frac{2\pi DN}{\sqrt{4H^2+D^2}})+2\pi DN \sqrt{4\pi^2D^2N^2+4H^2+D^2}}{8\pi DN}$$ 


Ltotal = length of the lighting needed, in feet

H = height of the tree canopy, in feet

D = diameter of the tree canopy, in feet

N = number of spirals from top to bottom, calculated as height divided by the light spacing plus one

From there, we simply divide the total length by the string length and round up to the nearest integer:

  • 70 bulbs with 4" spacing = 24 ft
  • 100 bulbs with 4" spacing = 33 ft
  • 100 bulbs with 6" spacing = 50 ft
  • 50 bulbs with 6" spacing = 25 ft
  • 25 bulbs with 8" spacing = 17 ft
  • 25 bulbs with 12" spacing = 24 ft