The job
Modelled, not recorded. Every figure here is the answer the Wall Plates, Headers and Cripples Calculator (Sole Plate, Head Binder, Lintel and Corner Studs) gives for these inputs, written down in both unit systems and re-run whenever the site is built. No job was carried out, so there is no measured overrun on this page.
The wall is the back wall of a single-storey addition: 24 ft (7.32 m) long, framed to 8.09 ft (2.47 m), the height a wall of precut studs on a bottom plate and a double top plate reaches. It has two windows and an exterior door, and it turns a corner at each end and meets one interior partition along its length.
The members are dimensional lumber 1.5 in thick at 16 in centres. The openings are entered as rough openings, 3.17 ft wide for each window and 3.17 ft for the door, with the window sills at 3 ft and the heads of all three at 6.87 ft, as a window and door schedule would give them.
The header depth, 9.25 in in 2 plies, is the size a header table gives for these spans in this wall; the calculator asks for it rather than choosing it, because sizing a header is structural and belongs to the table, the code and whoever designs the house. Its first source is the residential code's section on wood stud walls, which sets the double top plate and how plates overlap at corners.
The inputs, exactly as entered
| Input | Value | Why |
|---|---|---|
| Wall Run Length | 24 ft (7.32 m) | The wall's length along the bottom plate, corner to corner. |
| Framed Wall Height | 8.09 ft (2.47 m) | Floor to the top of the double top plate: a precut stud and three plates. |
| Stud Spacing (on centre) | 16 in (406.4 mm) | The standard spacing, entered exactly in inches so the stud length and cripples are counted on it. |
| Plate and Stud Thickness | 1.5 in (38.1 mm) | The actual thickness of dimensional lumber, which is what the plates stack to. |
| Top Plate | Double top plate (two plates) | Left at the calculator's own default. |
| Corners in This Run | 2 | Left at the calculator's own default. |
| Corner Framing | Three-stud corner (one stud more than the two wall ends) | Left at the calculator's own default. |
| Partitions Meeting This Run | 1 | Left at the calculator's own default. |
| Backing Where a Partition Meets | T-post: two studs in this wall | Left at the calculator's own default. |
| Windows | 2 | Left at the calculator's own default. |
| Window Rough Opening Width (each) | 3.17 ft (0.97 m) | Each window's rough opening width from the schedule, wider than the window itself. |
| Rough Sill Height | 3 ft (0.91 m) | Floor to the rough sill, which sets the cripples below each window. |
| Rough Sill | Single sill plate | Left at the calculator's own default. |
| Doors | 1 | Left at the calculator's own default. |
| Door Rough Opening Width (each) | 3.17 ft (0.97 m) | The exterior door's rough opening width. |
| Rough Opening Head Height | 6.87 ft (2.1 m) | Floor to the underside of the header, the same for the windows and the door. |
| Header Depth (from your header table) | 9.25 in (235 mm) | Read from a header table for these spans and loads; the calculator counts it, it does not size it. |
| Header Plies | 2 | Left at the calculator's own default. |
The working, step by step
1. Plates, bottom and top, along the run
72 ft (21.95 m)
One bottom plate and a double top plate run the full length of the wall: 72 ft. The bottom plate is usually cut out at the door after the wall is stood up, and the calculator leaves it in, which is how it is bought.
2. Stud length between the plates
7.72 ft (2.35 m)
The wall height less the three plates gives each stud's length, 7.72 ft. It is the figure every corner, junction and cripple piece is measured against, and it is why a wall of this height is framed with precut studs rather than cut ones.
3. Extra studs at corners
2 studs
A three-stud corner takes one stud more than the two wall ends already counted with the spacing: 2 studs for the two corners. That third stud gives the inside face something to fasten drywall to.
4. Extra studs at partition junctions
2 studs
Where the partition meets the wall, a T-post of two extra studs gives it something to fasten to and the drywall a backing on both sides: 2 studs. Together with the corner studs they come to 30.87 ft of lumber.
5. Window sills, lineal
6.33 ft (1.93 m)
Each window has a rough sill, a flat piece across the bottom of the opening, here single: 6.33 ft for the two windows. A door has none; its bottom plate is cut out instead.
6. Cripples below the sills
4 pieces
Under each sill, short cripple studs at the spacing carry it down to the bottom plate: 4 pieces. Their length is the sill height less the bottom plate, so a lower window means longer cripples.
7. Cripples above the headers
6 pieces
Above each header, short cripples fill the gap to the top plate: 6 pieces, because the header sits a little below the plate, 0.2 ft on this wall. All the cripples together come to 12.19 ft.
8. Header pieces
6 pieces
Each opening's header is built of 2 plies on edge, so the three openings take 6 pieces, 20.5 ft in all. The calculator keeps the headers in a section of their own, because they are bought in a deeper size than the plates and studs.
Lineal timber in the stud section
121.4 ft
37 m
The stud section is 121.4 ft of the same lumber as the studs, best bought in lengths that cut the plates and the corner studs with least waste; the headers, 20.5 ft, are a deeper member bought separately, with the spacer between the plies where the wall's thickness needs one. Add the studs at the spacing from the stud count, and the jacks and kings that carry each header, to finish the wall's list.
What to buy
| Quantity | Figure | What it is for |
|---|---|---|
| Lineal timber in the stud section | 121.4 ft (37 m) | Plates, corner and junction studs, sills and cripples in the wall's stud size, in lineal feet. |
The allowance, and what it does here
There is no waste percentage here: every piece is counted at its real length, so the waste is in how those lengths are cut from stock. A plate the length of the wall is cut from the fewest stock lengths that reach it, and the cripples and corner studs come out of offcuts if the order allows for it. Add a margin for culls, the crooked or split pieces set aside at the yard, and buy the plates as straight as the yard has.
The common mistake
Ordering a framed wall from its stud count alone
The stud count at the spacing is the number everyone takes off first, and on its own it leaves out a large share of the wall: the plates, which with a double top plate come to three times the wall's length, the corner and junction studs, every sill and cripple, and the headers. A wall ordered from the stud count is short of the pieces that hold the openings, which are exactly the ones a framer needs when the openings are cut. Run both calculators for every wall, and keep the headers on their own line in the order.
Change the job, and see what moves
The same wall, with a single top plate
Top Plate: Single top plate (tied at corners and splices) → 98.65 ft (30.07 m)
Frame the same wall with a single top plate, which the calculator's code source allows only where the plate is tied at corners, intersecting walls and splices, and the stud section falls to 98.65 ft. The plate run drops to 48 ft, and every stud gets a little longer to reach the same height.
The same wall, with two-stud corners on drywall clips
Corner Framing: Two-stud corner on drywall clips (none more) → 106 ft (32.3 m)
Build the corners with two studs and drywall clips instead of a third stud, and the section is 106 ft: the corner studs drop to 0 studs. The corner then has more room for insulation, which is the reason advanced framing uses it.
What to run next
- Framing Stud Calculator
The studs at the spacing, with the king and jack studs at each opening, are the rest of the same wall.
- Fenestration Rough Opening Calculator
Works the rough openings from the window and door sizes, which is where this wall's opening widths and heights come from.
- House Wrap Calculator
Once sheathed, the exterior wall is wrapped, counted in rolls from its area.
Sources
The method and every constant behind these figures belong to the Wall Plates, Headers and Cripples Calculator (Sole Plate, Head Binder, Lintel and Corner Studs), version 1.0.0, last verified 2026-10-10. It rests on:
- California Residential Code § R602.3.2 (the IRC's section of the same number): wood stud walls capped with a double top plate overlapping at corners and intersections with bearing partitions, plates 2 in nominal thick and as wide as the studs; a single top plate only where tied at corners, intersecting walls and in-line splices per Table R602.3.2, with the joists or rafters centred over the studs
- U.S. DOE Building America Solution Center, Advanced Framing: Insulated Corners — exterior wall corners are typically framed with three studs; a two-stud corner uses drywall clips or a nailing strip
- U.S. DOE Building America Solution Center, Advanced Framing: Insulated Interior/Exterior Wall Intersections (updated 2022-09-16) — the traditional T-post is two studs in the exterior wall where the interior wall meets it; ladder blocking is short 2x4 sections laid flat between the exterior studs either side of the intersection, 24 inches apart
- APA – The Engineered Wood Association, Advanced Framing construction guide, form M400 (revised 2016): stud spacing, corners, interior wall intersections, headers, openings, blocking and single top plates
- Southern Pine Inspection Bureau, "Nominal vs. Actual Lumber Sizes": dressed sizes per PS 20-20, the American Softwood Lumber Standard; a nominal 2-inch framing member dresses to 1 1/2 in
- Travis Perkins, CLS studwork timber 38 mm x 89 mm (kiln dried, regularised, C16): the UK studwork section
Frequently asked questions
- How much lumber for the plates of a 24 ft wall?
- With a double top plate and a bottom plate, 72 ft. With the corner and junction studs, the sills and the cripples the stud section comes to 121.4 ft.
- How many cripple studs does a window need?
- It depends on the opening's width and the spacing. On this wall the two windows and the door take 4 pieces below the sills and 6 pieces above the headers.
- Does the calculator size the headers?
- No. It counts the header pieces, 6 pieces here, at the depth taken from a header table; the size is a structural decision for the table, the code and the designer.