Drywall sheets by room calculator.

Worked example

A 12 x 10 ft room with 8 ft walls has 2 x (12 + 10) x 8 = 352 sq ft of wall and 12 x 10 = 120 sq ft of ceiling, 472 sq ft in all. A 4 x 8 sheet covers 32 sq ft, so 472 / 32 = 14.75, which rounds up to 15 sheets. Ten 4 x 12 sheets (48 sq ft each) cover the same room, and with 40 sq ft of openings deducted the 4 x 8 count drops to 14.

Method and sources

Formulas: wall area = 2 × (length + width) × height; ceiling area = length × width; net area = walls + ceiling − openings; sheets = ceil(net × (1 + waste%) / sheet area). Panel sizes: the Gypsum Association GA-223-04, Gypsum Panel Products Types, Uses, Sizes, and Standards lists 48 in. wide panels in 8, 9, 10, 12, 14 and 16 ft lengths and a 54 in. x 12 ft panel, and notes that not all types are available in all lengths, widths and thicknesses (retrieved 2026-10). Limits: this is an area estimate. Actual layout, vertical versus horizontal hanging, joints that must land on framing and off-cuts can need more sheets than the area suggests, so lay out the walls before ordering. The waste allowance is yours to set.

FAQ

How many sheets of drywall for a 12 x 10 room?

With 8 ft walls and a ceiling, the room is 472 sq ft, which is 15 sheets of 4 x 8 before waste, or 10 sheets of 4 x 12.

What sizes does drywall come in?

The Gypsum Association GA-223 chart lists 48 in. wide panels in 8, 9, 10, 12, 14 and 16 ft lengths, and 54 in. x 12 ft. Not every thickness or type comes in every size.

Should I subtract windows and doors?

Enter their combined area in the openings box and it is deducted. Leave it at zero if you would rather keep the margin.

Why not just use total square feet?

You can, with the general drywall calculator. This version builds the area from room dimensions, handles several rooms, and shows how the count changes with panel length.