How this is worked out
The walls are the room's perimeter times its height. Each door takes off 20 sq ft and each window 12, the size of a 3' × 6' 8" door and a 3' × 4' window, so nobody has to measure them. The ceiling is the length times the width. Add 10% for waste, or what you type, divide by one sheet and round up. An exact fit doesn't buy an extra sheet.
The tape, compound and screws are worked from the board you hang, not the sheets you buy, because offcuts are never taped. The figures are the CGC/USG Gypsum Construction Handbook's: 370 ft of tape and 9 gallons of ready-mixed compound per 1,000 sq ft, and screws 16" apart on walls and 12" on ceilings. Every length is rounded to the nearest sixteenth first, the way Handyman Calc does it.
For common rooms already worked out, there's a drywall sheets chart with a PDF to print.
On your phone, on the job site
On a phone, Handyman Calc has this drywall screen with prices for the sheets and mud, and fourteen more calculators. It works with no signal, and it's free.
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Charts worked out with the same math:
- how many bags of concrete a slab takes
- how many sheets of drywall a room takes
- a fraction to decimal chart for inches
- how much paint a room takes
- how much mulch a bed takes
- a roof pitch chart
- how many steps a rise takes
- the diagonal that squares a frame
- board feet for common lumber
More calculators:
Frequently asked questions
How many sheets of drywall do I need for a 12x12 room?
13 sheets of 4 × 8 for the walls of a 12 × 12 room with 8 ft walls, one door and one window, with 10% for waste. With the ceiling it's 18.
How many sheets of drywall for a 10x12 room?
11 sheets of 4 × 8 for the walls, or 16 with the ceiling, for 8 ft walls with one door and one window and 10% waste.
How do you calculate drywall?
Add the room's length and width, double it for the perimeter, and multiply by the wall height. Take off about 20 sq ft for each door and 12 for each window, and add the ceiling if you're boarding it. Add 10% for waste and divide by the sheet's area: 32 sq ft for a 4 × 8, 48 for a 4 × 12. Round up.
Should I use 4x8 or 4x12 sheets?
Longer sheets mean fewer butt joints, which are the hard ones to finish, so a 12 ft wall is usually hung with 12 ft sheets. The area is the same either way. A 4 × 12 is heavy, though, and harder to get up a stairway.
How much joint compound and tape do I need?
About 370 ft of tape and 9 gallons of ready-mixed compound per 1,000 sq ft of board, the figures in the CGC/USG Gypsum Construction Handbook. That's two 4.5 gallon pails for 1,000 sq ft, finished in three coats.
How many screws per sheet of drywall?
About 32 on a 4 × 8 wall sheet with screws 16" apart, and 40 on a ceiling sheet at 12". The calculator counts one screw per square foot of wall and 1.25 per square foot of ceiling.