Yardstickly

Drywall and plasterboard calculator

How many sheets of drywall or plasterboard for a room, with the doors and windows taken off.

Measure in

Decimals work everywhere. On a keyboard you can also type 10' 6" or 3 1/2.

What do you know?
Room size
ft
ft
ft
Area to cover
sq ft
Sheets
ft
ft
%
Add prices for a cost estimate

How it works

Wall area = 2 × (length + width) × height. We take off about 21 sq ft (1.9 m²) for each door and 15 sq ft (1.4 m²) for each window, add the ceiling if you tick it, add your cutting allowance, and divide by the area of one sheet. Screws are a rough count at about one per square foot of board (about 11 per m²); your fixing pattern sets the real number.

Worked examples

A 12 × 12 ft room with 8 ft walls, one door, one window and the ceiling, in 4 × 8 ft drywall with 10% waste: walls 384 sq ft, less 36 sq ft of openings, plus a 144 sq ft ceiling, is 492 sq ft. With waste that's 17 sheets.

A 4 × 3.5 m room with 2.4 m walls, one door and one window, in 2400 × 1200 mm plasterboard, needs 13 boards with 10% waste.

Which sheet size?

Longer sheets mean fewer joins to tape and fill, but they're heavy and awkward to get into a room. In the US and Canada, 4 × 8 ft sheets are easiest to handle, and 4 × 12 ft sheets hung horizontally can cover a wall in two rows with no end joins. In the UK and Australia, 2400 × 1200 mm is the standard board, with longer sheets for high ceilings. For a ceiling, a second person or a board lifter makes the job much safer.

Openings and waste

Many installers don't take small openings off at all, because the offcuts rarely fit anywhere else. If your room has lots of corners, soffits or a sloped ceiling, raise the waste to 15%.

Common questions

How many sheets of drywall for a 12 × 12 room?

With 8 ft walls, one door and one window, the walls take about 12 sheets of 4 × 8 ft drywall with 10% waste. Add 5 more for the ceiling.

How many sheets of plasterboard for a room?

Measure the perimeter, multiply by the wall height, and divide by 2.88 m² for a 2400 × 1200 mm board. A 4 × 3.5 m room with 2.4 m walls needs about 13 boards with 10% waste.

How many screws per sheet of drywall?

Roughly 30–40 per 4 × 8 ft sheet, depending on stud spacing and the fixing pattern for walls or ceilings. Follow the pattern in the board maker's instructions.

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