Ordering too little drywall means a mid-project supply run; ordering too much wastes money. Our drywall calculator estimates sheets, screws, and joint compound from your room’s basic dimensions.
Step 1: Total wall area
Perimeter = 2 × (length + width)
Wall area = Perimeter × ceiling heightThis assumes a simple rectangular room without subtracting door and window openings — treat the result as a solid starting estimate rather than a final material order.
Step 2: Sheets, with waste built in
Divide wall area by your chosen sheet size (32 sq ft for standard 4×8 sheets, or 48 sq ft for 4×12 sheets), then add a 10% waste allowance — a common contractor rule of thumb covering awkward cuts around corners, outlets, and openings that can’t always be reused.
Step 3: Screws and joint compound
The calculator estimates roughly 1.5 screws per square foot (matching typical 16-inch stud spacing with screws placed every 12-16 inches), and about 1 gallon of joint compound per 500 sq ft of drywall for taping and finishing seams.
Example
A 12ft × 10ft room with an 8ft ceiling: 352 sq ft of wall area, 13 sheets of 4×8 drywall (with waste), 528 screws, and about 0.8 gallons of joint compound.
Choosing sheet size
4×8 sheets are easier to handle solo and common for DIY projects; 4×12 sheets cover more area per sheet (fewer seams to tape on taller walls) but are heavier and usually need two people to install safely.