Measuring drywall area
For a rectangular room, gross wall area = 2 × (length + width) × height. For an irregular space, enter each wall width and height separately. Subtract the unboarded area of doors and windows. Add ceiling area if selected. Multiply the remaining area by (1 + waste percentage ÷ 100), divide by one sheet's surface area and round up to whole sheets.
A room example you can check
A 12 × 10 ft room with 8 ft walls has 352 sq ft of walls. Remove one 21 sq ft door and two 12 sq ft windows to get 307 sq ft of walls. Add the 120 sq ft ceiling: 427 sq ft. With 10% extra this becomes 469.7 sq ft; using 4 × 8 ft sheets (32 sq ft each), 15 sheets are estimated.
Sheet layout and finishing materials
Area-based results do not optimize seam placement, offcuts or sheet orientation. Drywall boards are sold in different lengths and thicknesses; check local suppliers and fire/moisture specifications. Optional tape and compound are simple rate-based allowances that you can edit. They are not a detailed joint-counting takeoff.
Can openings be larger than the walls?
No; the form will display an error if door and window deductions exceed the total wall area. Ceiling area is treated separately.