The Christmas Tree Lights Calc estimates the number of lights needed for a Christmas tree based on the tree's size and your desired spacing (density).
INSTRUCTIONS: Choose units and enter the following:
- (h) Height of Tree
- (b) Diameter of Base
Number of Lights (nL): The calculator returns the total number of lights needed to cover the tree (cone) with lights.
Covered
Natural
Sparse
Brilliant
Dense
The Math / Science
How many lights do you need for your Christmas tree? It depends! How big is your tree? How spread-apart do you want your lights? This calculator helps you figure these things out. First, you need to know the approximate size of your tree. The examples in this calculator will have a tree that is 8 feet (96") high and 60 inches wide. The next question is how dense do you want the lighting? Here's a guide:
- Brilliant - one light every 4 square inches
- Dense - one light every 9 square inches
- Covered - one light every 16 square inches
- Natural - one light every 36 square inches
- Sparse - one light every 144 square inches
Product Facts
Christmas tree lights typically come in stringers of length:
- 17ft
- 25 ft
- 35 ft (e.g. Lowe's Holiday Living 450 Minis)
- 43 ft (e.g. GE Pro-Line 150-Count White Minis)
The stringers can potentially have different bulb separations:
- 3"
- 6"
- 8"
- 12"
Advice
Safety first: Make sure you don't create a health and safety hazard. Here's a link to a government guide on inspecting your lights.
Nonetheless, conventional wisdom says to start on either the top or bottom and work in a spiral progressing from one to the other (bottom to top or vice versa). A good trick to spacing is to step back and squint. This makes the images of the bulbs blurred and enlarged, and can help you identify areas that you've missed.
Christmas Calculator
- Christmas Tree Lights Calc: Estimates the number of lights needed for a Christmas tree based on the tree's size and your desired spacing (density).
- Height of a Christmas Tree Topper: Computes the appropriate height of the ornament or angel to go on top of a Christmas Tree based on the height of the tree.
- Length of Christmas Tree Garland: Estimates the length of garland to be strung on a Christmas tree based on its height.
- Length of a Spiral Christmas Garland: Estimates the length of a Christmas Garland or Christmas Lights needed to wind around an object (e.g. railing) based on the length covered, spacing between spirals and the diameter of the spirals.
- Fabric for Circular Christmas Tree Skirt: Computes the appropriate diameter of a skirt for your Christmas tree given the tree's diameter at the bottom and also tells you the amount of fabric needed to make it.
- Fabric for Octagon Christmas Tree Skirt: Computes the appropriate diameter of a skirt for your Christmas tree given the tree's diameter at the bottom and also tells you the amount of fabric needed to make it.
- Number of Christmas Tree Baubles: Estimates the number of ornaments needed for a Christmas tree based on the size of the tree.
- [[Day until Christmas (12/25/2025), 346 days]]!
