A 4×8 ft sheet covers 32 square feet. Divide your total surface by sheet area, then add waste for cuts around doors, windows, and odd walls. Ten percent is a practical starting point for rooms that are not full of openings.
Joint tape is often estimated near 370 linear feet per 1,000 square feet of board. All-purpose compound for taping and a thin coat is often planned around 1 gallon per 100 square feet—always check the bucket.
Measure each wall as width × height, add the ceiling, subtract big openings if you want a tighter buy.
USG-style panels with walls and ceilings split live on the Sheetrock calculator. After the mud dries, finish with the wallpaper calculator or the tile calculator.
How this calculation works
sheets = ceil(area × (1 + waste) ÷ (sheet width × length)). Tape and mud use trade rules of thumb.