Drywall Calculator

US & Canada

Enter the room size to get the drywall sheets and screws to buy, for walls and ceilings, in the sheet size you want.

Your room

1. Room size

ft
ft
ft

2. Openings

doors
windows

Each door takes off 20 sq ft and each window 15 sq ft. Many installers sheet over small windows and cut them out, so set windows to 0 for a safer count.

3. Sheets

%

Result

0

Shopping list

Screws at the maximum spacing in GA-216 section 5.4 (16 in on walls, 12 in on ceilings for 16 in framing), with sheets hung across the framing. Fire rated assemblies can need more.

How the drywall maths works

  • Wall area = 2 × (length + width) × height − openings
  • Sheets = area × (1 + waste) ÷ sheet area, rounded up, walls and ceiling counted separately
  • Screws = framing members crossed × screws per member, per sheet

Screw spacing follows the Gypsum Association's GA-216, section 5.4: no more than 16 in apart on walls and 12 in on ceilings where framing is 16 in on centre, and 12 in on both where framing is 24 in on centre. Fire rated assemblies follow their own tested schedule.

Sheets for common rooms

4 × 8 sheets, 8 ft walls, one door and one window, 10% waste, studs at 16 in.

Drywall sheets and screws for common room sizes
Room Walls only Walls and ceiling Screws
10 × 10 ft 10 14 420
10 × 12 ft 11 16 483
12 × 12 ft 12 17 511
12 × 16 ft 15 22 665
14 × 16 ft 16 24 728
20 × 20 ft 21 35 1,078

Before you buy

  • Use the right board. Moisture resistant board for bathrooms, fire rated Type X where your code calls for it (garage walls shared with the house, for example).
  • Ceilings first. Hang the ceiling, then the walls, so wall sheets support the ceiling edges.
  • Tape and compound depend on the number of seams and how many coats you apply; check the coverage on the product.

Common questions

How many sheets of drywall do I need for a 12x12 room?
With 8 ft walls, one door and one window, a 12 × 12 room needs 12 sheets of 4 × 8 for the walls and 17 including the ceiling, with 10% waste.
How many sheets of drywall for a 10x10 room?
Walls and ceiling of a 10 × 10 room with 8 ft walls take 14 sheets of 4 × 8 with 10% waste.
How many sheets of drywall for 1,000 square feet?
A 4 × 8 sheet covers 32 sq ft, so 1,000 sq ft of wall plus 10% waste is 35 sheets. Remember that 1,000 sq ft of floor has far more wall and ceiling area than that.
How many screws per sheet of drywall?
Hung across studs at 16 in centres, a 4 × 8 sheet takes about 28 screws on a wall (16 in spacing) and 35 on a ceiling (12 in spacing). These are the maximum spacings in GA-216 section 5.4; many installers add more along the edges.
Should I subtract windows and doors?
Subtract doors. For windows, many installers hang full sheets and cut the openings out afterwards, so subtracting them can leave you short. Set windows to 0 for a safer count.
Are bigger sheets better?
Longer 4 × 10 and 4 × 12 sheets mean fewer seams to tape and finish, which saves time and gives a flatter wall. They are heavier and harder to move into a basement or up stairs, so plan the route first.