How many USG Sheetrock panels do I need?
Work out the area to board - the walls (room perimeter × ceiling height) plus the ceiling if you are boarding it - then divide by the panel area and add wastage. A 4 × 3 m room with 2.4 m ceilings and the ceiling boarded is about 45.6 m²; with 1.2 × 2.4 m panels (2.9 m² each) and 10% wastage that is 18 panels. Enter your room above for the exact count.