How the calculator works
Sheets are surface area with 10% waste divided by sheet coverage. The consumables scale off area using standard trade rates: roughly 32 screws per sheet (one every 12″ on edges, 16″ in the field), one 4.5-gallon bucket of ready-mix compound per 450 sq ft of board for a three-coat finish, and 37 feet of tape per 100 sq ft.
Worked example: a 14 × 12 room with 8 ft ceilings has 416 sq ft of wall plus a 168 sq ft ceiling = 584 sq ft… call it 640 with the closet. That's 22 four-by-eight sheets, ~700 screws, 2 buckets of mud, and 237 ft of tape.
Choosing sheets
- ½″ regular: standard for walls on 16″ centers.
- ⅝″ Type X: fire-rated, required on garage walls adjoining living space and many ceilings; also stiffer and quieter.
- ½″ moisture-resistant (green/purple): baths and laundry, but not inside showers, which is cement board's job.
- Sheet length: 12-footers run a wall in one piece and eliminate butt joints, the hardest joints to hide. Use them anywhere two people can maneuver.
Hanging order and small mercies
Ceilings first, then walls, since wall sheets support the ceiling edges. Hang horizontally on walls: it bridges more studs, adds rigidity, and puts the joint at a comfortable finishing height. Mark every stud on the floor and ceiling before the first sheet goes up; finding studs behind hung board is archaeology.