How to measure
Use these guides to identify the measurements the calculator needs. Drawings are not to scale.
C · Wall height: measure vertically from floor to ceiling. Four walls have area 2 × (length + width) × height; the ceiling is length × width.
For openings, multiply each opening’s width by its height and add the areas. Exclude only openings in the surfaces selected. For irregular rooms, calculate separate rectangles or enter a known total surface area.
From area to sheets
A 12 × 10 ft room with 8 ft walls has 352 sq ft of wall area. Adding 10% extra gives 387.2 sq ft. Divide by 32 sq ft for a 4 × 8 ft sheet and round upward: 13 sheets.
How it works
The geometry uses four rectangular walls and an optional rectangular ceiling, or a known surface area you enter. Deduct excluded openings once. Then add the selected extra percentage and divide by panel area. Sheet choices are 4 × 8, 4 × 10, and 4 × 12 ft; metric labels show those same products, not different regional sheet sizes.
The USG installation and finishing guide provides panel coverage and approximate supporting-material rates. The calculator scales its per-1,000-sq-ft figures using area with extra: 2.7 lb Type W screws, 370 ft tape, and 10 US gallons all-purpose compound or 9 US gallons Plus 3. For the example above, that gives about 1.05 lb screws, 143.26 ft tape, and 3.87 US gallons all-purpose compound. These are linear planning estimates, not package counts or an installation schedule.
Keep the cut plan and product requirements separate from the area estimate. This tool does not select panel thickness, framing, fastener type, or fire/moisture ratings. Compound coverage excludes full-surface skim coating.
Ready for the finish? Use the paint calculator. The result link carries your dimensions across; review paint coverage and coats before buying.