How Many Sheets of Drywall Do I Need? Chart by Room Size

Work out the wall area, take off doors and windows, add about 10% for cuts, and divide by the area of one sheet. A 12 × 12 ft room with 8 ft walls, one door and one window takes 12 sheets of 4 × 8 ft drywall for the walls, or 17 with the ceiling. In metric, a 4 × 3.5 m room with 2.4 m walls takes 13 boards of 2400 × 1200 mm plasterboard.

Sheets are counted by area, then rounded up. Offcuts from one row often fill the end of the next, which is why a 10% allowance is usually enough.

Drywall sheets by room size

Sheets of drywall for a room with 8 ft walls, one door and one window, including 10% for cuts
Room	Wall area	4 × 8 ft, walls	4 × 12 ft, walls	4 × 8 ft, walls and ceiling
10 × 10 ft	284 sq ft	10	7	14
10 × 12 ft	316 sq ft	11	8	15
12 × 12 ft	348 sq ft	12	8	17
12 × 14 ft	380 sq ft	14	9	19
14 × 16 ft	444 sq ft	16	11	23
16 × 20 ft	540 sq ft	19	13	30

Metric: plasterboard for a room with 2.4 m walls, one door and one window, including 10% for cuts
Room	Wall area	2400 × 1200 mm boards	1800 × 900 mm boards
3 × 3 m	25.5 m²	10	18
3 × 4 m	30.3 m²	12	21
4 × 4 m	35.1 m²	14	24
4 × 5 m	39.9 m²	16	28
5 × 6 m	49.5 m²	19	34

What size does drywall come in?

US and Canada: drywall is 4 ft (48 in) wide. USG lists its Sheetrock panels at 8 to 12 ft long; HomeAdvisor says lumber yards also sell 4½ ft widths and lengths of 9 and 16 ft. A 4 × 8 ft sheet covers 32 sq ft and a 4 × 12 ft sheet 48 sq ft.
UK: British Gypsum makes Gyproc WallBoard in 12.5 mm boards from 1800 × 900 mm to 3600 × 1200 mm; 2400 × 1200 mm (2.88 m²) is the common size.
Australia: Gyprock plasterboard comes 1200 or 1350 mm wide, in lengths of 2400, 2700 and 3000 mm and longer.

Which way to hang the sheets

HomeAdvisor suggests 4 × 8 sheets vertically for walls up to 8 ft, 4 × 9 sheets vertically or 4½ ft sheets horizontally for 9 ft walls, and sheets as long as the wall is high for 10 ft walls and above. Longer sheets mean fewer joins to tape, but they're heavier to carry and lift.

Worked example: a 12 × 12 ft bedroom

Walls: 4 × 12 ft = 48 ft of wall, × 8 ft high = 384 sq ft.
Take off one door (21 sq ft) and one window (15 sq ft): 348 sq ft.
Add the ceiling, 12 × 12 = 144 sq ft: 492 sq ft.
Add 10% for cuts: 541.2 sq ft. Divide by 32 sq ft per sheet: 16.91, so 17 sheets.

The drywall calculator does this for any room and sheet size, and gives a rough screw count.

How much extra?

HomeAdvisor's advice is to add 10%, or at least two extra sheets, especially if you're new to hanging drywall. Rooms with lots of corners, short walls, sloped ceilings or small offcuts that can't be used elsewhere waste more.

Common mistakes

Taking off every opening in full. Small openings such as outlets and switch boxes are cut out of whole sheets, so don't subtract them.
Forgetting the ceiling. It's often the biggest single surface in the room, and ceilings may need a different board.
Mixing up board types. Bathrooms and kitchens often call for moisture-resistant board, and some walls need fire-rated board. Count each type separately.