A 14 × 12 ft room, walls and ceiling
room length 14 ft, room width 12 ft, wall height 8 ft, Walls + ceiling, doors 1 pcs, windows 2 pcs, sheet size 32 ft².
Drywall sheets to buy
19 sheets
- Area to cover: 532.9 ft²
- Sheets (32 ft² each): 19
Drywall Calculator
This drywall calculator works out how many sheets of drywall a room needs from its size, doors, windows and sheet size, with a waste allowance included.
Last updated
How many sheets of drywall do I need for a 12 × 12 ft room?
With 8 ft walls, one door, two windows, the ceiling included and 10% waste, you need 524.6 ft² of board, which is 17 sheets of 4 × 8 ft.
Drywall sheets to buy
19 sheets
- Wall area
- 416 ft²
- Ceiling area
- 168 ft²
- Openings subtracted
- − 51.1 ft²
- Area to cover
- 532.9 ft²
- Area incl. 10% waste
- 586.2 ft²
- Sheets (32 ft² each)
- 19
Inputs
- Room length: 14 ft
- Room width: 12 ft
- Wall height: 8 ft
- Surfaces to cover: Walls + ceiling
- Doors: 1 pcs
- Windows: 2 pcs
- Sheet size: 32 ft²
- Waste / overage: 10 %
- • Joint tape, compound, screws and corner bead are not included. Ask your supplier to total them from your area.
- • Choose the longest sheet you can handle. Fewer joints mean less finishing.
Results are estimates for planning only. Supplier specifications, product yields, site conditions and local codes vary. Confirm quantities with your supplier or a qualified professional before you buy or build.
How this is calculated
Formulas
- Wall area = 2 × (length + width) × height. Ceiling area = length × width.
- Area to cover = walls and ceiling − (doors × door area) − (windows × window area).
- Area with waste = area to cover × (1 + waste %).
- Sheets = area with waste ÷ area per sheet, rounded up.
Assumptions
- The room is rectangular with a flat ceiling.
- A door is about 21 ft² (1.95 m²) and a window about 15 ft² (1.4 m²).
- Waste of 10% covers cut-offs and breakage. Rooms with many corners or openings can need more.
- Joint tape, compound, screws and corner bead are not included.
Worked examples: common projects
A 20 × 20 ft garage ceiling with 4 × 12 ft sheets
room length 20 ft, room width 20 ft, wall height 8 ft, Ceiling only, doors 0 pcs, windows 0 pcs, sheet size 48 ft².
Drywall sheets to buy
10 sheets
- Area to cover: 400 ft²
- Sheets (48 ft² each): 10
A 12 × 12 ft bedroom, walls and ceiling
room length 12 ft, room width 12 ft, wall height 8 ft, Walls + ceiling, doors 1 pcs, windows 2 pcs, sheet size 32 ft².
Drywall sheets to buy
17 sheets
- Area to cover: 476.9 ft²
- Sheets (32 ft² each): 17
A 4.2 × 3.6 m room, walls and ceiling
room length 4.2 m, room width 3.6 m, wall height 2.4 m, Walls + ceiling, doors 1 pcs, windows 2 pcs, sheet size 2.88 m².
Drywall sheets to buy
19 sheets
- Area to cover: 47.8 m²
- Sheets (2.88 m² each): 19
Quick reference
Drywall sheets by room size
8 ft walls, one door, two windows, walls and ceiling, 4 × 8 ft sheets, 10% waste.
| Room size | Area to cover | Sheets |
|---|---|---|
| 10 × 10 ft | 368.9 ft² | 13 |
| 12 × 12 ft | 476.9 ft² | 17 |
| 12 × 14 ft | 532.9 ft² | 19 |
| 14 × 16 ft | 652.9 ft² | 23 |
| 16 × 20 ft | 844.9 ft² | 30 |
Common sheet sizes
| Sheet | Area |
|---|---|
| 4 × 8 ft | 32 sq ft |
| 4 × 10 ft | 40 sq ft |
| 4 × 12 ft | 48 sq ft |
| 1.2 × 2.4 m | 2.88 m² |
| 1.2 × 3.0 m | 3.6 m² |
Before you buy drywall
Sheets are sold in several sizes. A 4 × 8 ft sheet covers 32 square feet, a 4 × 12 ft sheet covers 48. Longer sheets mean fewer seams to tape and finish, so use the longest you can carry and hang. Enter the area of your sheet and the calculator counts in that size.
Thickness does not change the sheet count, but it does matter for the job: walls and ceilings often use different thicknesses, and some areas need moisture-resistant or fire-rated board. Check local code and the product guidance. For the paint that follows, use the paint calculator.
Hanging and finishing notes
Hang ceilings first, then walls, and stagger the joints so seams do not line up. Keep sheet edges off the floor slightly to leave a gap for baseboard. Plan seams away from the middle of a wall where you can, and finish them with tape and compound in thin, feathered coats.
Frequently asked questions
How many sheets of drywall for a 12 × 12 room?
With 8 ft walls, one door, two windows, walls and ceiling, 10% waste and 4 × 8 ft sheets, you need 17 sheets.
Should I subtract doors and windows?
Large openings, yes. The calculator subtracts a standard size for each door and window you enter, and the waste allowance covers the offcuts.
How much extra drywall should I buy?
About 10% is typical. Rooms with many corners, angled walls or lots of openings need more.
Does this include joint compound and screws?
No. Those depend on the product and the finishing level. Ask your supplier to total them from the area shown here.
Is 4 × 12 drywall cheaper to hang than 4 × 8?
It often needs fewer joints, which means less finishing, but the sheets are heavier and harder to carry. Choose the longest size you can handle comfortably.
How many sheets for a garage ceiling?
A 20 × 20 ft ceiling is 400 square feet. With 10% waste that is 440 square feet, which is 10 sheets of 4 × 12 ft or 14 sheets of 4 × 8 ft.
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Results are estimates for planning only. Supplier specifications, product yields, site conditions and local codes vary. Confirm quantities with your supplier or a qualified professional before you buy or build.