Drywall Calculator
Calculate how many sheets of drywall (4×8 or 4×12) you need for walls and ceilings, subtracting doors and windows.
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Total Sheets Needed
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Wall Sheets —
Ceiling Sheets —
Net Drywall Area —
How to Use This Calculator
- Enter the room dimensions and ceiling height.
- Enter the number of doors and windows.
- Select sheet size and whether to include the ceiling.
- Results show sheets needed for walls and ceiling separately.
Formula
Wall area = 2(L+W)×H − doors×20 − windows×15
Sheets = ceil(Total area ÷ Sheet area × (1 + waste%))
Example
Example: 12×14 ft room, 9 ft ceiling, 1 door, 2 windows → Wall area 448 sq ft → 16 sheets of 4×8 (10% waste).
Frequently Asked Questions
- Divide the total paintable area (walls + ceiling minus openings) by the sheet area (32 sq ft for 4×8 sheets), then add 10–15% waste.
- 4×8 sheets (32 sq ft) are easiest to handle. 4×12 sheets (48 sq ft) reduce seams on tall walls and are common in professional work.
- Add 10% for simple rectangular rooms, 15% for rooms with many corners and openings, and up to 20% for complex shapes.
- The calculator deducts a standard door (20 sq ft) and window (15 sq ft) for each one you enter.
- Yes — enable the ceiling option to include the ceiling area in the total sheet count.