12×12 · 8 ft · 1 door · 2 windows
Input
10% waste · 4×8 sheetsOutput
12 sheets333 net sq ft × 1.10 ÷ 32 = 12 sheets.
Drywall sheet count uses **wall area ÷ sheet size**, with optional opening deductions and waste buffer.
**Room mode:**
Gross wall sq ft = 2 × (L + W) × wall height
Net sq ft = gross − doors − windows
Sheets = ceil(net × (1 + waste%) ÷ sheet sq ft)
**Example — 12×12 room, 8 ft walls, 1 door, 2 windows, 32 sq ft sheets, 10% waste:**
Gross 384 sq ft − 51 sq ft openings = 333 net
333 × 1.10 ÷ 32 = **12 sheets**
Perimeter wall area minus openings, divided by sheet sq ft, with waste buffer.
Formula
sheets = ceil(net_wall_sq_ft × (1 + waste%) / sheet_sq_ft)Tap 12×12 bedroom, 400 sq ft walls, or basement finish on the main form.
Ceiling height in feet — multiplies room perimeter for gross wall area.
Enable door and window deductions — adjust counts on the main form.
32 sq ft for 4×8 standard — or 40/48 sq ft for longer panels.
Results show sheets to order, net wall area, and purchase guide.
Input
10% waste · 4×8 sheetsOutput
12 sheets333 net sq ft × 1.10 ÷ 32 = 12 sheets.
Input
Area mode · no bufferOutput
12 sheets379 net sq ft ÷ 32 = 11.8 → 12 sheets.
Input
12×12 room · 8 ft wallsOutput
12 sheets384 ÷ 32 = 12 sheets exactly.
Common real-world scenarios where this tool saves time.
333 sq ft net walls, 10% waste, 32 sq ft sheets = 12 panels.
Area mode with one door — sheet count from total wall sq ft.
Large finish job — order extra for complex soffits.
Step-by-step chains that connect related tools for common tasks.
| Size | Sq ft | Best for |
|---|---|---|
| 4 × 8 ft | 32 | Standard 8 ft walls |
| 4 × 10 ft | 40 | 9 ft ceilings — fewer seams |
| 4 × 12 ft | 48 | Tall walls — less taping |
| Factor | Drywall sheets | Paint gallons |
|---|---|---|
| Unit | 4×8 panels | Gallons per coat |
| Typical waste | 10% | 10% cut-in |
| Next step | Tape, mud, sand | Primer + finish coats |
Drywall uses **wall** area — perimeter × height or total wall sq ft.
Outlet cuts and corner scraps need **10% minimum**.
Paper face color varies — buy one delivery lot.
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With 8 ft walls, gross wall area is 384 sq ft. After 1 door and 2 windows (~51 sq ft), net is 333 sq ft. At 10% waste and 32 sq ft sheets: 12 panels.
Standard 4×8 ft sheet = 32 sq ft. 4×10 = 40 sq ft. 4×12 = 48 sq ft.
Yes for whole-room estimates — each standard door is ~21 sq ft and window ~15 sq ft.
10% for simple rectangular rooms. 15% for many outlets, corners, or soffits.
Sheetrock is a brand name for gypsum drywall — sheet math is the same.
Yes — area mode accepts total paintable wall sq ft directly.
After drywall is mudded and sanded, use Paint Calculator for primer and finish coat gallons on the same wall area.
Enter ceiling sq ft in area mode — same sheet size and waste math.
Same sheet dimensions — use green or purple board sq ft count, not tile backer.
Partial panels are not sold — cuts at doors and corners always waste material.
Room dimensions stay on your device.
Estimates only — vaulted ceilings and complex soffits may need professional takeoff.
Part of Calculator Tools
More free tools for the same workflow.
Free paint calculator: enter wall area, coverage from your can, and coats → gallons or liters to buy. Room presets, door/window deductions, waste buffer, can round-up. Runs locally in your browser.
Free wallpaper calculator: room size, roll dimensions, and pattern repeat → rolls to buy. Room and accent-wall presets, waste buffer. Runs locally in your browser.
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Reviewed on 2026-06-27.
32 sq ft per sheet
4×8 ft = 32 sq ft (standard)
Standard door ≈ 21 sq ft (3×7 ft)
Standard window ≈ 15 sq ft (3×5 ft)
| Package size | To buy |
|---|---|
| 4 × 8 ft | 32 sq ft · Standard wall panel |
| 4 × 10 ft | 40 sq ft · Tall wall — fewer seams |
| 4 × 12 ft | 48 sq ft · 9 ft ceilings |
| 4 × 4 ft | 16 sq ft · Patch repairs |