Drywall and plasterboard calculator
Sheets for walls and ceilings, in US and metric sizes
Type the room size and pick the sheet. The example is a 12 x 14 ft room with 8 ft walls and the ceiling, in 4 x 8 ft sheets.
–
- Area to cover
- –
- Walls
- –
- Ceiling
- –
- Sheets before the extra
- –
An estimate of quantity from the sizes you typed, not an order list or a price. Check structural work, and anything covered by a building code, with your local code or a qualified person.
How the sheets are counted
- Walls = (length + width) x 2 x wall height, less any openings you type.
- Ceiling = length x width.
- Sheets = total area plus the allowance, divided by the area of one sheet, rounded up.
Most estimators do not take off ordinary doors and windows, because the pieces cut out are rarely big enough to use elsewhere. Take off big openings, such as a wide patio door.
Worked example
Room 12 x 14 ft with 8 ft walls: (12 + 14) x 2 x 8 = 416 sq ft of wall, plus a 168 sq ft ceiling, is 584 sq ft. Add 10%: 642.4 sq ft. A 4 x 8 ft sheet is 32 sq ft, so 642.4 / 32 = 20.1, which rounds up to 21 sheets.
Sheet sizes
US drywall is 4 ft wide, in 8, 10 and 12 ft lengths. UK plasterboard and Australian plasterboard (often called gyprock) are usually 1200 mm wide, in 2400 mm and longer lengths. Longer sheets mean fewer joints but are heavier to handle.
What it leaves out
Joint compound, tape, screws, corner bead and adhesive are not counted. The calculator does not pick a thickness or type: fire-rated, moisture-resistant and sound boards are set by the local code for each room, so check it or ask a qualified person.
Defaults and where they come from
Every default is only a starting point. Change any box to match what you are buying or building.
| Default | Value | Source |
|---|---|---|
| US sheet sizes | 4 x 8, 4 x 10, 4 x 12 ft | Standard 4 ft wide gypsum board sizes sold in the US (ASTM C1396 covers the board). |
| Metric sheet sizes | 1200 mm wide; 2400, 2700, 3000, 3600 mm long | Common UK plasterboard (BS EN 520) and Australian plasterboard (AS/NZS 2588) sizes. Check what your supplier stocks. |
| Waste allowance | 10% (usual 10 to 15%) | Common trade practice for off-cuts and damaged sheets. No standard sets a figure. |