Free Drywall Screws calculator with clear step-by-step results.
Screw count comes from two spacings multiplied together: how many studs a board crosses, and how many screws go into each stud along the board's length. Both counts add one for the end fixing, and a waste allowance covers the screws that strip, snap or vanish into the floor.
Screws per board
Studs crossed x screws per stud, where each = floor(dimension / spacing) + 1
Total screws
Total = ceil(screws per board x boards x (1 + waste))
Around 200 mm on walls and 150 mm on ceilings for single-layer board. Check the board manufacturer's fixing schedule, especially for fire-rated or acoustic systems where spacing is specified.
Yes - edge fixings are usually closer and must sit at least 10 mm in from a cut edge. That detail is inside the waste allowance rather than modelled separately.