How much drywall do I need?
For each room, the wall area is the perimeter times the wall height. The ceiling is length times width. Subtract doors and windows, add 10% for waste, and divide by the sheet size.
Sheets = (2 × (L + W) × height − openings + L × W) × 1.10 ÷ sq ft per sheet
A 12 × 12 ft bedroom with 8 ft walls has 2 × 24 × 8 = 384 sq ft of wall. Take out one door (21 sq ft) and one window (15 sq ft) and you have 348 sq ft. The ceiling adds 144 sq ft, for 492 sq ft in total. With 10% waste that's 541 sq ft: 17 sheets of 4 × 8, or 12 sheets of 4 × 12.
| Sheet size | Sq ft per sheet | Sheets per 1,000 sq ft (no waste) |
|---|---|---|
| 4 × 8 ft | 32 | 31.3 |
| 4 × 10 ft | 40 | 25 |
| 4 × 12 ft | 48 | 20.8 |
Longer sheets mean fewer butt joints to finish, but they're heavier and harder to get through a house. Many pros hang 4 × 12 where they can.
Drywall calculator for walls and ceiling
Enter each room's floor size and set the wall height once. Pick walls and ceiling, walls only, or ceiling only. In the bedroom above, the walls alone take 12 sheets of 4 × 8 and the ceiling 5 more.
Many crews hang 5/8 in board or sag-resistant 1/2 in board on ceilings, especially when the framing is 24 in on center. Garage walls and ceilings next to living space often need fire-rated board. Check your local code.
How much drywall mud do I need?
One 4.5 gallon bucket of all-purpose joint compound typically covers 400–500 sq ft of drywall for taping plus a fill coat and a finish coat. The calculator uses 450 sq ft; change it if your crew runs heavier or lighter. The 492 sq ft bedroom takes 1.1 buckets, so buy 2.
| Per 1,000 sq ft of drywall | Typical amount |
|---|---|
| All-purpose joint compound | About 2.2 buckets (10 gal) |
| Paper tape | About 370 ft |
| Screws | About 1 per sq ft (32 per 4 × 8 sheet) |
Lightweight compound covers more area per pound but about the same per gallon. Outside corners also need corner bead, which the calculator doesn't count.
Doors and windows
The calculator takes out 21 sq ft per door (3 × 7 ft) and 15 sq ft per window (3 × 5 ft). Some hangers don't subtract small openings at all, because the cutouts end up as waste anyway. Count a sliding door or a large window as two.
Pricing a drywall job
Drywall contractors usually price per square foot of board, or per sheet, for hanging and finishing. The finish level matters: Level 4 is typical under flat paint, and Level 5 (a skim coat over everything) costs more. Use contractor mode to add labor and markup, then send it as a quote with the handyman estimate template.
Questions
How many sheets of drywall do I need for a 12 × 12 room?
With 8 ft walls, one door, one window and the ceiling, about 17 sheets of 4 × 8 including 10% waste. Walls only, about 12 sheets.
How much drywall mud do I need?
Typically one 4.5 gallon bucket of all-purpose joint compound per 400–500 sq ft of drywall, for tape and two more coats. That's about 2 to 3 buckets per 1,000 sq ft.
How much drywall tape do I need?
About 370 ft of paper tape per 1,000 sq ft of drywall. A 500 ft roll covers roughly 1,350 sq ft.
How many screws per sheet of drywall?
About 32 for a 4 × 8 sheet, or roughly one per square foot. Ceilings use closer spacing than walls, so follow the board maker's schedule.