C9 / C7 bulb count
Convert roofline or outline feet into socket/bulb counts for C9 or C7 stringers at your spacing.
Formula
sockets = ceil(linear_feet ÷ (spacing_inches ÷ 12)) · add spare % for peaks and replacements
12 in ≈ 1 bulb/ft (common C9). 6 in doubles density.
Math is the same; label helps you match packs and clips.
FAQ
How many C9 bulbs per foot?
At 12-inch spacing you need about one socket per foot. At 6-inch spacing you need about two per foot.
Should I order extras?
A 5–15% spare buffer covers broken bulbs, peaks, and color-pattern leftovers.
Does this work for C7 too?
Yes — enter the same linear feet and your C7 stringer’s socket spacing.
What about gables?
Measure each rake and ridge run, then sum the linear feet before dividing by spacing.