Calculators/ Interior/Drywall Calculator
Drywall Calculator
Sheets, screws, tape and compound for a room.
Drywall is cheap but hanging it twice is not, so the sheet count matters. This includes a 10% allowance built in, because almost every wall produces offcuts too small to use anywhere else.
How this is calculated
- Wall area = perimeter × ceiling height, minus doors and windows. The perimeter is 2 × (length + width).
- Add the ceiling area if you are boarding it, which is simply length × width.
- Divide by the sheet area and add 10% for offcuts. A 4 × 8 sheet is 32 square feet; longer sheets mean fewer butt joints to finish.
- Allow about 32 screws per sheet, 0.37 linear feet of tape per square foot of board, and one gallon of compound per 100 square feet for three coats.
Frequently asked questions
What size drywall sheets should I use?
Longer sheets mean fewer butt joints, which are the hardest joints to hide. Use 12 foot sheets if you can physically get them into the room; 8 foot is the practical maximum for most stairwells and retrofits.
Should drywall be hung horizontally or vertically?
Horizontally on walls in residential work. It puts the tapered joint at a convenient height, reduces total joint length and adds rigidity across studs.
How much joint compound do I need?
About one gallon per 100 square feet of board for a standard three-coat finish. A level 5 skim coat needs roughly half again as much.