How to use the stud calculator
Framing a wall takes more than the studs on the layout grid. Corners, intersecting walls and every window and door add extra pieces, while openings remove some common studs. This calculator counts each group so you get a realistic order for one wall or a whole floor (enter the total length of walls with the same height and spacing).
- Enter the wall length and height in feet or metres.
- Choose stud spacing and size. 16 in (400 mm) is standard; 24 in (600 mm) is common with 2×6 studs.
- Pick single or double top plates and enter the plate stock length you will buy.
- Count corners and T-intersections along the wall, where extra studs give backing for the drywall.
- Enter doors and windows with their rough opening widths. The rough opening calculator works these out from the unit size.
Stud wall framing formulas
Common studs = ⌈length ÷ spacing⌉ + 1
Extras = 2 × corners + 2 × T-intersections + 4 × openings (2 king + 2 jack)
Replaced studs per opening ≈ ⌈opening width ÷ spacing⌉ − 1
Cripples ≈ replaced studs × (2 per window, 1 per door)
Stud length = wall height − (1 + top plates) × plate thickness
Plates = ⌈length ÷ stock⌉ × (1 + top plates) · header = opening + 2 × plate thickness, 2 plies
Cripples are short, so the calculator assumes each full stud yields two cripples. The replaced-stud and cripple counts depend on where the openings fall on the layout, so treat them as estimates. Corners and intersections are taken as 2 extra studs each, which matches a common three-stud corner; ladder blocking or two-stud corners use fewer.
Worked examples
20 ft exterior wall with a door and two windows
At 16 in on center: ⌈240 ÷ 16⌉ + 1 = 16 common studs. Two corners add 4, and three openings add 12 kings and jacks. The 38 in door replaces ⌈38 ÷ 16⌉ − 1 = 2 studs and each 36 in window replaces 2, so 6 come off: 16 + 4 + 12 − 6 = 26 full-length studs. Cripples: 2 above the door plus 4 per window = 10, cut from 5 studs. With 10% waste the order is ⌈31 × 1.1⌉ = 35 studs, each 91½ in for an 8 ft wall with a double top plate.
Plates and headers
A 20 ft wall with 16 ft plate stock needs 2 pieces per plate run, so 6 pieces for one bottom and two top plates. Headers are 38 + 3 = 41 in for the door and 39 in for each window, doubled: about 19.8 ft of header stock.
Metric partition
A 4.8 m partition at 600 mm spacing with a single top plate: ⌈4,800 ÷ 600⌉ + 1 = 9 studs, 2,400 − 2 × 38 = 2,324 mm long for a 2.4 m wall.
Who this calculator can help
- Architects and designers checking timber quantities and comparing 16 in and 24 in framing for cost and insulation space.
- Framers and contractors building a takeoff and lumber order for a house, addition or basement finish.
- Estimators pricing walls by the linear foot or metre.
- Homeowners and DIY builders framing a partition, garage wall or shed.
- Students learning how light-frame walls are laid out and counted.
Practical tips
- Lay out studs from one end so sheet joints land on a stud: 48 in sheets break on 16 in and 24 in spacing.
- Buy a few extra studs beyond the waste allowance for blocking, backing for cabinets and grab bars, and replacing twisted boards.
- Size headers from a span table or an engineer; this tool only gives their length.
- Next steps: cover the frame with the drywall calculator, fill it with the insulation calculator, price timber with the board foot calculator, and finish with the baseboard and trim calculator.
Have a framing sketch? Turn it into a finished interior view with AI Sketch to Render.
