Drywall Calculator
Estimate 4×8 drywall sheets, drywall screws, and joint tape needed to finish a room, accounting for doors and windows.
Results
What is it?
The Drywall Calculator estimates how many 4×8 sheets of drywall you need to cover the walls of a rectangular room. It subtracts door and window openings and adds a 10% overage for cuts and waste. It also estimates screw and joint tape quantities.
How to use
1. Enter the room length, width, and wall height. 2. Input the number of doors and windows. 3. The calculator returns sheets (with 10% waste), screws (≈64 per sheet), and joint tape (≈40 ft per sheet). 4. Purchase complete boxes of screws — they typically come in 1 lb boxes of roughly 350 screws.
Example scenario
A 14 × 12 ft bedroom with 9 ft ceilings, 2 doors, and 2 windows: wall area = 2×(14+12)×9 − 2×21 − 2×15 = 468 − 42 − 30 = 396 ft². Sheets = ceil(396/32 × 1.1) = ceil(13.6) = 14 sheets.
Pro tip
½-inch drywall is standard for interior walls; use ⅝-inch (Type X) for fire-rated assemblies and garage walls adjacent to living space. Always hang drywall horizontally — it is stronger and creates fewer butt joints to tape.