(NOTE: The following information is from christmaslightsetc.com.)
Recommended Number of Lights for Indoor and Outdoor Trees
How Many Lights for Indoor Christmas Trees?
Rule of Thumb: Christmas trees
- For medium lighting, plan 100 mini lights per vertical foot of the tree
- For heavy lighting, plan 200 mini lights per vertical foot
How Many Lights for Outdoor Trees?
There is no exact calculation to determine how many lights are required to light outdoor trees. Slender and deciduous trees will require the least amount of lights for desired affect. Evergreen trees including Spruce, Pines and Firs that retain most of their foliage in the winter may require up to 25% more lights than the recommended count shown.
Note: C9 bulbs are much larger than C7 bulbs and may overwhelm trees under 12′ tall.
Factors in Bulb Spacing and String Length
String length is a consideration when calculating how many lights are needed. 100 light count strings can come with various spacing between bulbs, resulting in string lengths that can differ by 15′ or more.
- Evergreen trees are thick, needing additional string length to ensure complete coverage. 6″ bulb spacing is ideal. Consider using C7 and C9 bulbs.
- Deciduous trees shed leaves, requiring fewer lights if simply draping and more if wrapping trunks and branches. 8″ spacing is ideal.
- Trunks and branches require higher light counts. Learn more through our dedicated resource page for Wrapping Outdoor Trees with Lights. For heavier lighting, 4-5 light strings should cover trunks and main branches. Many trunks can be wrapped with 1-2.
- Bushes and hedges – light counts remain standard, however many people choose to use net lights for quick and even coverage. When using light strings, choose random light patterns as opposed to uniform for best effect.
Popular Lights for Trees
The type of light string chosen makes a difference in light count. The most popular bulb sizes for trees are mini lights, 5mm wide angle LED bulbs, and C7 bulbs.
- Mini lights: the most popular bulb in Christmas tree lights for indoor and outdoor use
- Standard grade – 210 watts can be connected, (typically 600 bulbs)
- Premium grade – 210 watts can be connected (typically 600 bulbs), includes lamp lock to ensure bulb stays secure in the socket
- Commercial grade – 420 watts can be connected (typically 1,000 bulbs)
- 5mm LED lights: the preferred LED bulb size for indoor Christmas trees. The concave lens design of a wide angle LED bulb produces a much brighter halo of light than that found in an incandescent mini light. The result of this difference in design is less bulbs required per foot when using 5mm LED mini lights.
- Over 3,000 5mm LED bulbs can be connected together – approximately 48 sets of lights.
- C7 bulbs: a popular bulb size among Christmas enthusiasts for to its retro appearance and timeless design. Because they are larger in size and light output, far less C7 bulbs are required for tree lighting than mini lights. C7 bulbs and strings can be purchased individually for complete design customization and are also available in convenient all in one prelamped light sets with the bulb and light string already paired for quick installation!
- C9 bulbs: intended for large and overly dense or tall outdoor trees. The largest of the recommended types of lights for trees, C9 bulbs are often reserved for outdoor trees 15′ and above as they produce a high impact light display that may be overwhelming when used on smaller tree varieties. C9 bulbs and strings can be purchased individually for complete design customization and are also available in convenient all in one prelamped light sets with the bulb and light string already paired for quick installation!
Light Calculations for Power
Every Christmas lighting project requires light calculations for power. Lights will burn brighter and last longer when the proper calculations are used to determine how many lights can be plugged together. The UL standard for how many lights can be connected has recently changed, allowing for up to 210 watts to be plugged together on a standard 22 gauge wire, and 410 watts on a commercial grade 20 gauge wire. C7 bulbs vary greatly depending in wire gauge used, which can be as thick as 18 gauge, allowing for up to 100 C7 bulbs to be connected.
- To best determine how many Christmas lights you need, we recommend lighting counts based on:
- Indoor Christmas trees
- Lights for outdoor Christmas trees
- Bushes and hedges
- Wrapping trunks and branches
- Hanging Christmas lights on rooflines and down walkways
- Wattage Needs
- Before the decorating begins, plug up each string to test it. It is a lot easier to correct any issues before the lights are on the tree.
- Christmas trees: When stringing lights, start from the top of the tree and work your way to the bottom. The female end of the plug can be connected to the tree topper.
- Christmas trees: Run the light strings along the inside of the tree branches to give the tree more depth.
- Outdoor trees: Start at the base of the tree, work your way up the trunk and branches, and back down.
- Personal preference is the ultimate deciding factor, so while these are recommended counts, you should be safe increasing or decreasing the bulb