Wall Framing Calculator
Studs, plates, headers and noggins for a timber-framed wall.
Quantity take-off for a straightforward stud wall. Header sizing, loadbearing capacity and racking resistance are structural questions and depend on span, load and code.
How it works
A stud wall is a comb: studs at fixed centres between a bottom plate and a top plate, with extra framing round every hole in it.
Common stud count is the wall length divided by the spacing, plus one for the end. The fencepost rule again — a 6 m wall at 400 mm centres takes 16 studs, not 15, and the last bay is usually short rather than a full spacing.
Openings are where the count grows. Every door or window needs a king stud each side running full height, a jack (or trimmer) inside it carrying the header, and cripples above the header and below the sill to keep the sheathing supported at the right centres. That is four extra studs minimum per opening plus the cripples, and it is why a wall full of windows uses more timber than a solid one rather than less.
The double top plate is not decoration. Its laps are staggered from the joints in the plate below, which ties the wall lengths into a continuous member and lets joists or trusses land anywhere along it rather than only over a stud.
Noggins — blocking, dwangs, depending where you are — go in at mid-height to stop the studs twisting and to give a fixing for anything heavy. One row is standard on a 2.4 m wall; two on anything taller.
Spacing is the choice that carries the most weight. 400 mm centres is stronger, gives better fixing for plasterboard and is required for some loads; 600 mm uses about a third less timber and is fine for a non-loadbearing partition. Check what your board thickness needs before deciding — 12.5 mm plasterboard at 600 centres sags noticeably on a ceiling.
Common questions
400 or 600 centres?
600 for a non-loadbearing partition — a third less timber and quicker to build. 400 where the wall carries load, where the sheathing needs the support, or where you want the extra fixing points. Board thickness matters: thin plasterboard at 600 centres is noticeably soft between studs.
Why so many studs around a window?
King stud, jack stud, and cripples above and below. The king runs full height and is nailed to the header; the jack sits inside it and actually carries the header down to the plate; the cripples fill the gaps so the boarding still has fixings at the right centres.
Do I need a double top plate?
For a loadbearing wall, effectively yes — the staggered laps tie the wall together and let a joist land anywhere rather than only over a stud. A non-loadbearing partition inside a finished building can get away with a single plate.
How much waste should I allow?
Studs are bought at length and cut to height, so the offcut is waste unless the height suits a stock length exactly. Buy 5% extra for bowed and twisted pieces you will reject at the rack — every bundle has some.