Framing Calculator
Work out the studs, plates and header lumber to frame a wall, from its length, height and stud spacing, with corners, doors and windows, stud length and board feet.
How to Use
- Enter the wall length and height (floor to the top of the top plate).
- Choose the stud spacing: 16 in on centre is most common, 24 in for many exterior walls; 400 or 600 mm in metric.
- Enter the number of corners and wall intersections this wall has, and its doors and windows with their typical width.
- Choose the lumber size and the length plates are bought in, and keep about 10% for waste.
- Read the studs, plates, stud length and board feet; add a price per stud for the cost.
Worked Example
An exterior wall 20 ft long and 8 ft high at 16 in centres, with one door, one window and a corner at each end. Common studs: 20 × 12 = 240 in, ÷ 16 = 15 spaces, plus 1 = 16 studs. Corners add 2 × 2 = 4, and the two openings add 4 each (two kings and two jacks) = 8, for 28 studs; with 10% waste, 31. Plates: one bottom and two top, 3 × 20 = 60 ft, which is six 10 ft pieces. Each stud is 96 − 4½ = 91½ in long.
The common mistake: dividing without adding the last stud. 240 ÷ 16 gives 15 spaces between studs, but a wall needs a stud at both ends, so 16. Leaving off the end stud, and then the extras at corners and openings, is why stud counts come up short on site.
Show Work
Formulas
Platform Framing
Most North American houses are built with platform framing: each floor is a platform, and walls are built flat on it, then tilted up. Studs sit between a bottom plate and a top plate, and openings are framed with headers that carry the load around them to jack studs. It replaced balloon framing, where studs ran the full height of two storeys, mainly because shorter lumber was easier to get and each floor blocked fire from spreading up inside the walls.
A 2×4 is not 2 in by 4 in: dressed and dried, it is 1½ × 3½ in (38 × 89 mm), and a 2×6 is 1½ × 5½ in. The nominal size is the rough-sawn size before drying and planing. Board feet, used to price hardwood and some framing lumber, are counted on the nominal size.
About This Calculator
This calculator counts the studs for a wall at any common spacing, including the end stud, corners and intersections, and king and jack studs for doors and windows; it gives the plates in the stock length you buy, the stud length, header stock, board feet and cost. It works in feet and inches or in metres, with 400 and 600 mm spacing.
Everything runs in your browser; nothing is sent anywhere. It is an estimate for ordering; header sizes and stud spacing for load-bearing walls come from your local code or an engineer.
Related calculators: Lumber Calculator, Drywall Calculator, and Insulation Calculator.
Frequently Asked Questions
How many studs do I need for a wall?
Divide the wall length in inches by the spacing and add one for the end: a 20 ft wall at 16 in centres needs 240 ÷ 16 + 1 = 16 studs. Then add two for each corner or wall that joins it, and about four for each door or window (two king and two jack studs). A quick rule is one stud per foot of wall at 16 in centres.
How long are wall studs?
The stud is the wall height minus three plates of 1½ in: one bottom plate and a doubled top plate. Precut studs are sold for standard walls: 92⅝ in for an 8 ft ceiling (wall 97⅛ in, leaving room for 8 ft drywall plus the ceiling), 104⅝ in for 9 ft and 116⅝ in for 10 ft.
What does 16 inches on center mean?
The distance from the centre of one stud to the centre of the next is 16 in. It lines up with 4 ft sheets of drywall and sheathing: every 48 in falls on a stud, so sheet edges always have something to fasten to. 24 in spacing (also a 48 in divisor) uses fewer studs and leaves more room for insulation.
What are king and jack studs?
At each door or window, a full-height king stud runs beside the opening, and a shorter jack (trimmer) stud next to it carries the header that spans the top of the opening. Short cripple studs fill the space above the header and below a window sill, keeping the regular spacing for the sheathing.
Why is the top plate doubled?
The second top plate ties walls together at corners and intersections, where its joints overlap the plate below, and it spreads loads from joists or rafters that do not land directly on a stud. Some advanced-framing designs use a single top plate with metal ties and aligned framing.
How do I use the Framing Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Do I need to install or sign up for anything?
Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.
Is my information private?
Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.
Common Use Cases
Plain wall
A 20×8 ft wall at 16 in centres: 16 studs, with 3 runs of plate in two 10 ft pieces each.
Exterior wall with openings
The same wall with a door, a window and two corners: 16 + 4 + 8 = 28 studs, 31 with 10% waste.
24 in spacing
A 40 ft wall at 24 in centres has 21 studs instead of 31 at 16 in, ten fewer.
Basement partition
A 12 ft partition 8 ft high with one door: 10 + 4 = 14 studs, plus pressure-treated lumber for the bottom plate.
Metric wall
A 6 m wall at 600 mm centres needs 11 studs; at 400 mm, 16.
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