How to use the framing and stud calculator
Add a wall and type its length. Pick the wall height, and the page works out the stud length from your plates. Add each door and window as a rough opening: how far its left edge is from the left end of the wall, its width and height, and for a window the sill height. The Header button sets the header board, plies and jack studs. The answer shows the studs to buy, the pieces to cut and the plate boards to buy, and the picture builds the wall to scale. The One wall tab lists where to mark the plate. Nothing you type leaves your device unless you make a share link.
How the studs are counted
The page puts a stud at each end of the wall, then one centered every 16, 19.2 or 24 inches from the left end, the way a builder hooks a tape on the end and marks the plate. It drops a stud that would crowd the end stud, and adds one if the last bay is wider than the spacing. A plain 14 foot wall is 168 inches. At 16 inches on center the marks fall at 16, 32 and so on to 160: ten studs plus two end studs, which is 12. At 19.2 inches it is 10, and at 24 inches it is 8. In your head: divide the length by the spacing, add one, round up.
A window in the wall
Take that 14 foot wall at 16 inches, with a 36 by 48 inch window whose sill is 34 inches off the floor and whose left edge is 60 inches from the end, one jack stud a side and a double 2x8 header. The window needs a king stud and a jack stud on each side, so the studs that stood where the window is are taken out. The full-height studs drop from 12 to 11, counting the two kings. The window gets 2 jack studs, 2 cripples under the sill at 31 inches, 2 cripples over the header at 4 7/8 inches, one 36 inch sill board and a header of two boards 39 inches long. The header is longer than the opening because it sits on the jacks, between the kings. The calculator opens on this wall and this window, with a door added beside it; delete the door to see these exact numbers.
Kings, jacks, cripples, sills and headers
- King stud: a full-height stud beside each side of an opening.
- Jack stud (trimmer): a shorter stud nailed to the king that carries the header; its length is the height to the underside of the header less the bottom plate.
- Header: the board or boards across the top of the opening, carrying the load above it.
- Cripple: a short stud between the header and the top plate, or between the sill and the bottom plate, at the layout spacing.
- Sill: the flat board under a window's rough opening.
Headers: the page counts them and does not size them
This calculator does not choose a header. Its size depends on the span, what the wall carries, snow load and the width of the building, and that is a structural decision. In the IRC the header table is R602.7, read by floor and roof setup, snow load and building width, and the same table gives the number of jack studs. Load-bearing headers are not required in nonbearing walls. Your code edition and local amendments decide, so use your building department's table, an engineer, or the plans. Type the header you were given and the page counts and cuts it.
Spacing and plates
Stud size, height and spacing come from IRC Table R602.3(5), section R602.3.1. In general a 2x4 bearing wall that carries a floor and a roof is held to 16 inches on center, while many roof-only and nonbearing walls may go to 24. Walls normally have a double top plate whose end joints are offset at least 24 inches, with the plates overlapping at corners and intersections. A single top plate is allowed only with metal ties and with joists or rafters centered over the studs within an inch. The edition and the state matter, and these figures come from a summary of the 2025 California code, so confirm them in your own.
Corners and T's
A traditional corner uses four studs, a California corner uses three, and a corner with drywall clips or scrap backing can use two where the corner does not transfer shear between the walls. The Corners and T's tab adds the studs beyond the two the plan already counts. At a T you can use ladder blocking or one extra stud; the 24 inch block spacing is our default, not a code number.
Where the numbers come from
A nominal 2x4 is 1 1/2 by 3 1/2 inches and a 2x6 is 1 1/2 by 5 1/2, from the American Softwood Lumber Standard, PS 20. Precut studs are 92 5/8 inches for an 8 foot ceiling and 104 5/8 for a 9 foot ceiling: with one bottom plate and two top plates they reach walls of 97 1/8 and 109 1/8 inches. Boards are usually sold from 8 to 16 feet in 2 foot steps. The page works in inches, adds 1 1/2 inches per plate, and converts to metric with the exact 25.4 millimeters to the inch. Lumber keeps its US names in metric. The page counts boards and never adds a price.
Common mistakes
- Using the ceiling height as the wall height. The wall is taller than the ceiling by the plates; studs are the wall height less 4 1/2 inches with three plates.
- Measuring the opening, not the rough opening. Use the framed hole, not the door or window.
- Forgetting the extra width of the header. It sits on the jacks, so it is longer than the opening.
Questions
Does this size my header?
No. It counts and cuts the header you pick. Use the IRC header tables for your edition, your plans or an engineer.
How do I mark the plate?
Open One wall and use the list: the center of each piece from the left end, and the left edge, so you can mark with a square and set the stud on the mark.
Are there extra studs for waste?
You can type a percent. It starts at 10 and that is our own allowance, not a rule. It applies to studs and kings only.
Can I use metric?
Yes. Press Metric to type meters and millimeters. Lumber keeps its US names, a 2x4 is still a 2x4, and spacing becomes 400, 450 or 600 millimeters.
Can I share my result?
Yes. Share makes a link with a picture, a link you can copy, and a short video made on your device. The link keeps only the wall sizes and openings, for 90 days.