Enter the room size to see how many drywall sheets to buy, plus roughly how much mud, tape and screws.
How many sheets of drywall?
Sheets = (wall area + ceiling − openings) × (1 + waste) ÷ sheet area
A 12 × 14 ft room with 8 ft walls has 416 sq ft of wall and 168 sq ft of ceiling. Take off a door and two windows (50 sq ft) for 534 sq ft, add 10% waste, and divide by 32 sq ft per 4 × 8 sheet: 19 sheets.
Which sheet size?
Bigger sheets (4 × 12) mean fewer seams to tape and finish, but they're heavy and hard to carry through doors and up stairs. 4 × 8 sheets are easiest for one person. Use ½-inch drywall for most walls and ⅝-inch fire-rated (Type X) where code requires it, such as walls shared with a garage.
Supplies, roughly
- Joint compound: about 1 gallon of premixed mud per 100 sq ft.
- Paper tape: about 37 ft per 100 sq ft.
- Screws: about 32 per 4 × 8 sheet (closer spacing on ceilings).
These are estimates; buy a little extra and return what you don't use.
How we checked this
Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:
- 12 × 14 × 8 room with ceiling, 1 door, 2 windows: 19 sheets ✓
Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.
Questions people ask
How many sheets of drywall for a 12x12 room?
With 8 ft walls and the ceiling, about 528 sq ft. Less a door and two windows, plus 10% waste, that's 17 sheets of 4 × 8.
How much joint compound do I need?
Roughly 1 gallon of premixed compound per 100 sq ft of drywall, so a 4.5-gallon bucket finishes about 450 sq ft.
Should drywall go on the ceiling first?
Yes. Hang the ceiling first so the wall sheets help support its edges.