Net area first
Measure wall and ceiling area, then subtract doors and windows. On a 1,500 sq ft job with 100 sq ft of openings, you are estimating 1,400 sq ft — at 4×8 sheets and 10% waste, that is 49 sheets.
Consumables scale with the sheet count
- Screws: about 1 lb per 500 sq ft at 16-inch on-center framing.
- Tape: roughly 26 ft per sheet for typical joints; 500 ft rolls.
- Compound: a 5-gallon bucket finishes about 450 sq ft through three coats.
- Corner bead: measured lineal feet of outside corners — not derivable from area.
Sheet size is a labor decision
Twelve-foot sheets reduce butt joints — and taping labor — on long walls, but they handle harder and need the access to match. Put the choice in the estimate; it changes both material count and finishing hours.