About this calculator
Sheets for a whole room, walls and ceiling, with doors and windows deducted, plus the screws, joint compound and tape to finish them.
How it’s calculated
Wall area = perimeter × height − (doors × 20 sq ft) − (windows × 15 sq ft). Add the ceiling, add waste, and divide by the sheet area.
Finishing rates: about one 4.5 gal bucket of compound per 480 sq ft of board, and about 370 ft of tape per 1,000 sq ft.
Worked example
With these inputs:
- Room length
- 14 ft
- Room width
- 12 ft
- Wall height
- 8 ft
- Doors
- 1
- Windows
- 2
- Include ceiling
- Yes
- Sheet size
- 4 × 8 ft
- Waste allowance
- 12%
the result is:
- Drywall sheets
- 19 sheets
- Wall area (net)
- 366 sq ft
- Ceiling area
- 168 sq ft
Tips from the trade
- Hang sheets horizontally on walls. Fewer, lower butt joints are easier to finish.
- Longer sheets mean fewer joints but need more hands.
- Don’t deduct small openings. The offcuts rarely get used.
Common questions
How many sheets of drywall for a 12×12 room?
With 8 ft walls and a ceiling: about 16–17 4×8 sheets including waste.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and local building codes before ordering.