Free online framing calculator

How to use

1. Enter the wall length and height in feet.
2. Choose stud spacing — 16 in is standard residential.
3. Enter the number of doors and windows in the wall.
4. Set a waste factor (15% is typical).
5. Read stud count, plate footage, and board counts.

Formulas

base studs    = ceil(wallLength / (studSpacing / 12)) + 1
opening studs = (doors + windows) × 4   (2 king + 2 jack per opening)
cripple studs = windows × 2             (above rough sill)
total studs   = base + opening + cripple

plate linear ft = 3 × wallLength        (double top + single bottom)
header linear ft = openings × 3 ft each

raw linear ft = studs × wallHeight + plate linear ft + header linear ft
total linear ft = raw × (1 + waste% / 100)

boards (8 ft)  = ceil(totalLinearFt / 8)
boards (10 ft) = ceil(totalLinearFt / 10)
boards (12 ft) = ceil(totalLinearFt / 12)

Worked example

20-ft wall, 8-ft height, 16-in spacing, 1 door, 2 windows, 15% waste:

base studs    = ceil(20 / 1.333) + 1 = 15 + 1 = 16
opening studs = 3 × 4 = 12
cripple studs = 2 × 2 = 4
total studs   = 32

plate ft      = 3 × 20 = 60 ft
headers       = 3 × 3 = 9 ft
raw linear ft = 32 × 8 + 60 + 9 = 256 + 60 + 9 = 325 ft
total (15%)   = 325 × 1.15 ≈ 374 lin ft

8-ft boards   = ceil(374 / 8) = 47
10-ft boards  = ceil(374 / 10) = 38
12-ft boards  = ceil(374 / 12) = 32

Notes

• Order a few extra boards beyond the calculated count for any special cuts (corners, blocking, cripples around plumbing).
• Buy plates in 10-ft or 12-ft lengths to minimize splices; long plates also help align the wall.
• Pressure-treat the bottom plate if it rests on concrete to resist moisture.