Drywall Calculator — Sheets, Screws & Compound
Sheetrock math in seconds. Enter your room for exact 4×8 sheets, screws, joint compound, and tape — with waste built in. Free, instant, no signup.
Quick answer
Divide your wall area by 32 (one 4×8 sheet) and add 10% waste. A 12×12 ft room with 8-ft ceilings needs about 14 sheets, 450 screws, and one 5-gallon bucket of joint compound.
How do you want to measure?
10%
10% covers odd cuts around doors, windows, and outlets.
Your drywall estimate
4×8 sheets to buy
14
384 sq ft incl. 10% waste
- Drywall screws (≈)
- 448
- Joint compound (5-gal)
- 1
- Joint tape (250-ft rolls, ≈)
- 1
Screws and compound are estimates — pros always keep a spare box and bucket on hand.
How the calculation works
- Wall area: 2 × (length + width) × height for a rectangular room. Add the ceiling (length × width) if you're rocking that too.
- Sheets: area × 1.10 (waste) ÷ 32 sq ft per 4×8 sheet, rounded up.
- Screws: ~32 per sheet — every 12" on wall studs, 12" on ceiling joists.
- Joint compound: one 5-gallon bucket per ~450 sq ft for a three-coat finish.
- Tape: one 250-ft roll per ~500 sq ft of drywall.
Drywall thickness guide
| Thickness | Use it for |
|---|---|
| 1/4" | Curved walls, overlaying old drywall |
| 1/2" | Standard interior walls |
| 5/8" | Ceilings (no sag), fire-rated walls |
Tips from the pros
- Hang ceilings first, then walls. The wall sheets brace the ceiling edges.
- Stagger your seams like brickwork — stacked joints crack and telegraph through paint.
- Don't overdrive screws. The head should dimple the paper, not tear it. A drywall screw gun pays for itself.
- Three thin coats beat one thick one. Mud shrinks as it dries — build it up gradually.
- Sand with a light at an angle. Raking light reveals every ridge before primer locks it in.
Common questions
Calculate total wall area (2 × (length + width) × height for a room), add 10% for waste, and divide by 32 (one 4×8 sheet). Example: a 12×12 room with 8-ft ceilings = 384 sq ft × 1.10 = 422 ÷ 32 = 14 sheets.