LUMBER
FRAMING LUMBER COUNT
count = ⌈run·12 ÷ o.c.⌉ + 1
ft
ft
RESULT
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FILL IN ABOVE
Counts run-spacing pieces only. Add 2–3 studs per corner/T-intersection and 4 per opening for a full wall.
About this calculator
This framing lumber calculator handles four of the most common rough-framing counts: wall studs, floor joists, ceiling joists, and roof rafters. Pick the framing type, enter the room or wall dimensions, choose your on-center spacing, and the calculator returns the piece count plus the supporting numbers a framer or estimator actually wants — pre-cut stud length for walls, total linear feet for joists, rafter pairs and per-rafter horizontal span for roofs. Standard residential spacing is 16" o.c.; engineered floors and advanced framing often run 19.2" or 24" o.c.; 12" o.c. is used in heavy-load or short-span situations.
Common questions
What does "on center" or "o.c." mean?
On-center is the distance between the center of one framing member and the center of the next. 16" o.c. means studs (or joists, rafters) are spaced so the centers are 16 inches apart, regardless of how thick the lumber actually is. Standard residential framing is 16" o.c.; ceiling joists and engineered floors often run 24" o.c.; 19.2" appears in advanced framing layouts (a 5-on-8 pattern that lines up with 8-ft sheet goods); 12" o.c. shows up in heavy-load areas or short-span situations.
What pre-cut stud length should I order?
For an 8-ft wall, pre-cut studs are 92-5/8" — that gives a finished ceiling around 8'1-1/8" once the bottom plate (1-1/2") and double top plate (3") are added on. For 9-ft walls use 104-5/8", for 10-ft walls use 116-5/8". For non-standard heights, take the ceiling height in inches and subtract 4-1/2" — that's your stud cut length.
Do I need extras for corners and openings?
Yes. This calculator gives the run count along a single wall or joist line — corners, T-intersections, and openings are layout-dependent. Add 2–3 studs per outside corner (a 3-stud corner is the standard), 2–3 per T-intersection where another wall ties in, and 4 studs per door or window opening (2 jacks + 2 kings). Add cripple studs at 16" o.c. above and below openings as needed. A typical room ends up 6–12% over the run count.