A good rule of thumb is 100 lights for every 1.5 feet of tree. However, if you love lights, you may want to double, or even triple, that amount.
Add that in with string lights you may want in other areas, 5-10 boxes are a good start.
The rule of thumb, explained
100 lights per 1.5 feet of tree height works as a starting point because it assumes moderate
coverage — enough to look lit without being packed edge to edge. If you want a denser, more
saturated look (or you’re lighting a wide tree rather than a narrow one), doubling or tripling that
ratio is normal, not overkill.
Tree lighting vs. roofline lighting — different math
This rule of thumb is specifically for trees, where you’re wrapping bulb count around height and
width. A roofline is measured by length, not a bulb-per-foot ratio the same way — if you’re lighting
a roofline rather than a tree, use our roofline light
calculator instead, which matches your measured length to the right catalog set.
Worked example
A 6-foot tree at the base rule (100 lights per 1.5 ft) needs roughly 400 lights for moderate
coverage (6 ÷ 1.5 × 100 = 400) — that’s four of our 100-Light Mini LED sets, or two of the 200-Light 2-Pack. Want a denser, fuller look instead of just “moderate”? Double it to roughly 800.
Don’t forget the “other areas” 5-10 boxes
The original note above about 5-10 boxes for other areas (railings, doorways, bushes) is a rough
planning buffer, not a precise number — the actual amount depends entirely on what else you’re
lighting. If you’re specifically covering a roofline, measure it and use the calculator above rather
than estimating from a box count.
FAQ
Does the 100-lights-per-1.5-feet rule apply to outdoor rooflines too?
Not directly — that ratio is for wrapping a tree by height. For a roofline, measure the actual
length and use the roofline light calculator instead.
How do I know if I want “moderate” or “double/triple” coverage?
It’s a look preference — moderate reads as lit-but-not-packed, while doubling or tripling gives a
denser, more saturated look. Neither is wrong; it’s about how full you want the tree to look.
What if my tree is an unusual shape, not a simple cone?
Treat width the same way as height — a wide, bushy tree needs more lights per foot of height than
a narrow, columnar one for the same “moderate” look, since there’s simply more surface to cover.
Counting by height alone misses width
The height-based rule is a starting point rather than an answer, because two trees of identical
height can need very different amounts of light. A narrow columnar tree and a wide, full one at the
same height differ substantially in surface area, and surface area is what you are actually
covering. A wide tree wants noticeably more than the base ratio suggests; a slim one wants less.
The same applies to how you light it. Wrapping only the outer surface takes far less than
spiralling into the interior branches, which is a different project altogether — decide which look
you are after before converting the ratio into an order.
Indoor trees versus outdoor trees
An indoor tree is viewed from a few feet away, where individual bulbs are distinct and gaps are
obvious, so density matters and mini lights usually suit best. An outdoor tree is viewed from the
street, where the same density reads as a much softer glow and larger bulbs hold their definition
better — the bulb type comparison covers how
each type reads at distance.
Outdoor trees also need outdoor-rated sets and GFCI-protected power, which an indoor tree does
not: Christmas light safety
covers the difference, and it is not a formality — the failure mode outdoors is moisture at a
connection rather than anything to do with bulb count.
Warm white or multicolor changes nothing about the count
Worth stating plainly, because it comes up constantly: colour has no effect on how many sets a
tree needs. The ratio is about surface area and spacing, not about what colour the bulbs are, so
work out quantity first and choose colour separately —
warm white vs. multicolor covers that
decision on its own terms. The one caveat is consistency: if you are adding to an existing tree in
a later year, match the original product rather than just the colour name, since whites in
particular vary between sets.
Check the chain before you plug in
A well-lit tree can easily use several sets end to end, which brings the manufacturer’s connect
limit into play. The sets in our catalog range from 7 to 25 sets per chain —
connect limits has the per-product figures —
and exceeding it dims or flickers the far end, which on a tree usually means the top
(flickering LEDs).
Wrapping the trunk is a separate calculation
If you are lighting a trunk as well as foliage, the bulb-per-height ratio does not apply at all —
trunk wrapping is calculated from circumference and wrap spacing, and consumes more length than most
people expect. Wrapping a tree trunk
has that method, and for rooflines rather than trees,
measuring your roofline and
the roofline picks guide are the right
starting points.
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