A 12 × 12 ft room with 8 ft walls has 384 square feet of wall. Add 10% for waste and cuts, divide by 32 square feet per 4×8 sheet, and the walls take 14 sheets. The ceiling adds 144 square feet, so walls and ceiling together take 19 sheets of 4×8.
In 4×12 sheets it is 9 for the walls and 13 with the ceiling. Longer sheets leave fewer butt joints to tape, but they take two people to hang, and a drywall lift helps on the ceiling.
How the count is worked out
Drywall is counted by area. The walls run 48 ft around the room, 2 × (12 + 12), times 8 ft of height = 384 square feet. The ceiling is 12 × 12 = 144, for 528 square feet of board in all. Times 1.1 for waste that is 580.8 square feet; divided by 32 per 4×8 sheet and rounded up, 19 sheets.
Nothing is taken off for doors and windows here, so the cutouts cover mistakes and odd pieces. A standard 3 × 6' 8" door is 20 square feet and a 3 × 4 ft window is 12; take one of each off and the walls come to 352 square feet, or 13 sheets of 4×8 for the walls.
12x12 room: sheets by wall height (10% waste)
12x12 room: sheets by wall height (10% waste)| Wall height | Wall area (sq ft) | 4×8, walls | 4×8, walls + ceiling | 4×12, walls + ceiling |
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| 8' | 384 | 14 | 19 | 13 |
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| 9' | 432 | 15 | 20 | 14 |
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| 10' | 480 | 17 | 22 | 15 |
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Nearby room sizes: 4×8 sheets, 8 ft walls
Nearby room sizes: 4×8 sheets, 8 ft walls| Room (ft) | Wall area (sq ft) | Walls only | Walls + ceiling |
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| 10 × 10 | 320 | 11 | 15 |
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| 10 × 12 | 352 | 13 | 17 |
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| 12 × 12 | 384 | 14 | 19 |
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| 12 × 14 | 416 | 15 | 21 |
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| 12 × 16 | 448 | 16 | 22 |
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Screws, mud and tape
For the 528 square feet of walls and ceiling, USG rules of thumb per 1,000 square feet of board give about 528 screws on framing 16" on center, 5.3 gallons of ready-mixed all-purpose joint compound (2 × 4.5 gal pail) and 195 ft of paper tape (1 × 500 ft roll). A smoother level of finish takes more mud.
Hanging tips
Hang the ceiling first, then the walls with the sheets laid horizontally: on 8 ft walls two rows of 4 ft sheets cover the height with one seam at hand height, easy to tape. Walls taller than 8 ft need a strip at the bottom or taller sheets.
Keep the big offcuts for closets and over doors, and check the thickness your job calls for: 1/2" is common on walls, while ceilings and fire-rated walls may need 5/8". Local code decides where fire-rated or moisture-resistant board goes.
Frequently asked questions
How many sheets of drywall for a 12x12 room?
With 8 ft walls and 10% waste: 14 sheets of 4×8 for the walls only, 19 for walls and ceiling. Nothing is subtracted for doors or windows.
How many 4x12 sheets for a 12x12 room?
9 for the walls and 13 with the ceiling, with 8 ft walls and 10% waste.
How much joint compound and tape for a 12x12 room?
About 5.3 gallons of all-purpose compound and 195 ft of paper tape for the walls and ceiling (528 square feet of board), by USG rules of thumb: 2 × 4.5 gal pail and 1 × 500 ft roll.
Estimates only. Check measurements, product labels and local building codes before you buy or build.