Kit Builder — size a C9 or C7 install kit in seconds.
Enter the linear footage of the roofline you plan to light, pick a bulb spacing, and get a parts list for a complete install: socket-wire spool count, bulb count with overage, clip count, plugs, and photocell timer. Uses SPT-1 or SPT-2 socket-wire spool stock lengths (250-ft, 500-ft, 1,000-ft, 2,000-ft, 4,000-ft).
Uses standard stock spool lengths and 8 percent overage on bulbs and clips to cover install and take-down breakage. Adjust spacing or footage in the form to recalculate.
How the Kit Builder math works
Bulb count: total linear inches divided by bulb spacing gives raw bulb positions. Add an 8 percent overage to cover install-and-take-down breakage, then round up to the nearest 25-count pack.
Spool plan: greedy fit against stock spool lengths (250-ft, 500-ft, 1,000-ft, 2,000-ft, 4,000-ft). The plan prefers a single large spool if the job fits, otherwise stacks multiple spools with the smallest possible waste on the last spool.
Clip count: one clip per bulb position plus 8 percent overage, rounded up to 25-count packs. A different clip style may change the per-clip cost but not the count.
Plugs and timer: one male-plus-female plug pair per spool (line-in and end-of-run), one photocell timer per install line. Adjust for multi-line jobs.
Which wire gauge do I need?
SPT-1 (18 AWG) is the standard for residential Christmas light installs. SPT-2 (18 AWG with heavier insulation) is standard for commercial installs and required in some commercial jurisdictions by electrical code. Check the local electrical code before speccing SPT-1 on a commercial project.
Which clip should I pick?
Magnetic clips hold to metal fascia and standing-seam roofs — no other install surface can use them. Ridge clips hold on shingle ridges. All-in-one clips work on both gutters and shingles and are the most versatile clip in a general-use install kit. Shingle tabs work under the edge of a shingle course.