Recommended Number of Lights for Indoor and Outdoor Trees
How Many Lights for Indoor Christmas Trees?
Rule of Thumb: Christmas trees
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.
Indoor Christmas trees: For calculating the number of lights needed for indoor trees, plan for 100 lights per vertical foot.
Most popular: 4" bulb spacing to allow for maximum lighting with minimal wire
If wrapping branches: 6" or 8" spacing is recommended to allow space for wire to wrap tightly around each branch
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
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.