Drywall Calculator — m, sheets, tape & cost
How to use this calculator
Enter room dimensions in metres, centimetres or millimetres and the calculator returns plasterboard count, joint tape, mud buckets, screws and corner bead for the supply order. Deduct doors and windows so you do not over-order — a typical 3.6×4.2 m bedroom with one door and one window draws about 11 sheets of 12.5 mm 1200×2400 at 10% waste. The plan and elevation diagram redraws as you type; tap any dimension to jump to that input.
Tape & Mud — joint tape rolls (150 m/roll), joint compound (covers ~9 m² per coat), 2-3 coats.
Screws — approximately 10 screws per m², ~0.5 kg per 100 screws.
Cost — price per sheet, per tape roll, per mud bucket, per kg of screws. Currency selector: €, zł, Kč, kr.
Saved Calculations
| Time | Mode | Area m² | Sheets | Tape | Mud | Screws | Total |
|---|
How to Calculate Plasterboard for a Room (Metric)
Sheet counts follow EN 520 plasterboard coverage data and EN 13963 jointing practice (Knauf/Rigips/Gyproc field tables). Quantities are net-area driven and rounded up to whole units because partial boards, rolls and buckets are not sold. Allow 5% for a clean rectangular room, 10% for an average job, and 15–20% where there are many corners, soffits, returns or odd-angle cuts. Once the board is up, run the paint calculator on the same wall area to size primer and finish coats.
Formulas Used
Net area = gross wall or ceiling area − door openings − window openings.
Sheets = ceil(net area × (1 + waste%) ÷ sheet area), with sheet area 2.88, 3.60 or 4.32 m².
Joint tape = total board joints (≈ sheets × (sheet height + 1.2 m) ÷ 2) ÷ 150 m per roll.
Joint compound = net area ÷ 9 m² per coat × coats (2 for Q3, 3 for Q4 finish).
Screws ≈ 10 per m² (35 mm coarse-thread, ~0.5 kg per 100).
Frequently Asked Questions
What size plasterboard should I use? 1200×2400 mm is standard; 1200×3000 mm cuts joints on tall walls but is heavy and needs two installers. Use 12.5 mm for most walls and ceilings, and 15 mm fire board for EI 60 or acoustic assemblies per EN 520.
How much waste should I plan for? 10% suits typical rectangular rooms. Use 15–20% for cut-heavy layouts, and plan board orientation before cutting to keep offcuts usable.
What else do I need to finish? Pair this with the tile & grout calculator for wet areas, the flooring and carpet calculators for the floor, or the block wall calculator when the partition is masonry rather than studs.
On install day
Three things estimators forget. Hang ceilings first — walls support the ceiling board edges, so order ceiling sheets separately if you are running 15 mm overhead. Inside and outside corners — a 3.6×4.2 m room hides roughly 10 m of inside corners and 3–5 m of outside corners that the gross-area maths misses; add them to the corner-bead input or you will run short. Mud yield — a 25 kg bucket of ready-mix joint compound covers ~9 m² per coat at Q3, so a 35 m² room needs about 8 buckets across two coats. 2025 EU pricing runs €6–10 per 12.5 mm 1200×2400 sheet, €3–5 per 150 m roll of paper tape, €10–15 per 25 kg bucket of all-purpose mud. EN 13963 sets joint quality classes (Q1–Q4) — Q3 is standard for painted walls, Q4 for grazing light.
