How the drywall estimate works
The calculator measures the wall area from the room perimeter times wall height, subtracts standard openings (20 sq ft per door, 15 sq ft per window), adds the ceiling if included, then divides by the area of one sheet. A waste factor covers cuts around openings and broken edges.
Sheets = ceil( area x (1 + waste%) / sheet area )
Sheet size: why it matters
A 4x8 sheet covers 32 sq ft, 4x10 covers 40, and 4x12 covers 48. Bigger sheets mean fewer joints to tape and finish — a real labor saving on long walls — but they need two people or a drywall lift to hang. For standard 8-foot ceilings, 4x8 sheets fit height-wise with no horizontal cut; 9-foot walls suit 4x10s; 4x12s shine in long basements and hallways.
Screws and compound rules of thumb
Plan roughly 1 lb of 1-1/4 inch screws per 100 sq ft of board on walls (use 1-5/8 inch screws on ceilings and thicker board). For joint compound, a 4.5-gallon bucket of ready-mix typically finishes about 350 sq ft of board with taped joints, so a 400 sq ft room takes a bucket and a bit. These are planning figures — heavy texture coats change them.
Recommended tools & supplies
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Use cases
- Basement finish - long runs favor 4x12 sheets to cut joint work.
- Garage - 5/8-inch Type X board for fire separation walls shared with the house.
- Bathroom - moisture-resistant board near wet walls; cement board behind tile in showers.
- Ceilings - run perpendicular to joists; add the ceiling toggle above.