Stud Wall Calculator — Framing, Plasterboard & Insulation
Calculate studs, sole plates, top plates, drywall sheets and insulation for partition walls. Enter wall dimensions, choose stud spacing, and get a full material list including waste — for one or both sides of the wall.
How thick is a stud wall?
Stud depth plus the board on each face. A 48 × 98 mm timber stud with 12.5 mm plasterboard both sides finishes at 123 mm. The US equivalent is not a straight conversion: a real 2×4 is 3½ in deep, not 4, so with ½ in drywall both sides it finishes at 4½ in. Deeper 48 × 148 mm studs give 173 mm; a 2×6 gives 6½ in. Metal C-studs run 48, 70, 92 and 146 mm (1⅝, 2½, 3⅝ and 6 in webs), so a 92 mm / 3⅝ in partition finishes at 117 mm or 4⅝ in.
What spacing should wall studs be at?
Either 600 mm or 400 mm centres — 24 in or 16 in on centre. Use the closer spacing where boards need more support, where something heavy will be fixed to the wall, or where the insulation batt is sized for it. The count is wall length ÷ spacing rounded up, plus one stud to close the end, plus a doubled stud each side of every opening.
Wall diagram
Shopping list — 48×98 mm C24
Framework
Fasteners
Cladding
Insulation
Trims and surface
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How the stud wall calculator works
- 1Stud count: wall length ÷ stud spacing, rounded up, plus one end stud
- 2Add doubled studs at each side of any door or window opening
- 3Plate length: wall length per plate (sole plate = wall length; top plate = wall length; add a second top plate of the same length if load-bearing)
- 4Drywall sheets: wall area ÷ sheet area (e.g. 1.2 × 2.4 m, or 4 × 8 ft), with 10% waste
- 5Insulation: wall area ÷ batt coverage, one side only (mineral wool fills the stud cavity)
- 6Stud length = room height − 2× plate thickness (not floor-to-ceiling)
Worked example
Partition wall: 4.8 m long, 2.4 m high — 16 × 8 ft — with 600 mm stud spacing (24 in OC) and one 900 mm (3 ft) door opening, drywalled both sides.
You need 10 studs, 9.6 m total plate material (4.8 m sole plate + 4.8 m top plate), 9 drywall sheets in total (4.8×2.4 = 11.52 m² per side × 2 = 23.04 m², ÷ 2.88 m² per sheet × 1.10 waste = 8.8, rounded up to 9) and approximately 9.6 m² of mineral wool insulation (11.52 m² wall area minus 0.9×2.1 m door opening = 9.63 m²). In US sizes: 32 linear feet of plate, 248 sq ft of board face, and 9 sheets of 4 × 8 ft.
Frequently asked questions
What stud spacing should I use for a partition wall?
600 mm centres — 24 in OC — is standard for non-load-bearing partition walls with 12.5 mm (½ in) drywall. Use 400 mm spacing (16 in OC) for heavier tiles, shelving or higher acoustic requirements.
How many studs do I need per metre of wall?
At 600 mm spacing: approximately 1.7 studs per metre, or one every 24 in. At 400 mm spacing: approximately 2.5 studs per metre, one every 16 in. Always add one extra for the end stud.
How much drywall do I need for a 10 m² wall?
With standard 1.2×2.4 m sheets (2.88 m² each) — 4 × 8 ft, 32 sq ft — and 10% waste, you need approximately 4 sheets per side. Use the calculator to account for windows and doors.
What is the difference between load-bearing and partition walls?
Partition walls divide space only. Load-bearing walls carry the weight of floors or roof above. Never remove a wall without confirming it is non-load-bearing — consult a structural engineer if unsure.
What insulation should I use in a stud wall?
Mineral wool (rock wool or glass wool) is standard — it is fire-resistant, easy to cut and provides both thermal and acoustic insulation. 70–90 mm batts fit neatly in a 48×98 mm stud cavity; in US framing, a 3½ in batt fills a 2×4 bay.