How many sheets of drywall for a 12×12 room?

A 12×12 ft room with 8 ft ceilings has 4 walls totaling 384 sq ft of wall area, plus 144 sq ft of ceiling = 528 sq ft total. Subtract about 60 sq ft for a door and two windows, leaving 468 sq ft. A standard 4×8 sheet covers 32 sq ft. Dividing 468 ÷ 32 = 14.6 sheets. Adding 10% waste gives 16–17 sheets. For walls only (no ceiling), you would need about 11–12 sheets.

What thickness drywall for interior walls?

The standard thickness for interior walls in residential construction is ½ inch (12 mm). This is the most common drywall used throughout homes for walls and ceilings. Use ⅝ inch (15 mm) Type X for fire-rated assemblies such as garage walls adjacent to living space, around furnace rooms, or between units in multi-family buildings. Use ¼ inch (6 mm) for curved surfaces or as a second layer over existing drywall.

What is 12mm drywall in inches?

12mm drywall is ½ inch (0.472 inches exactly). This is the standard interior wall thickness used in North American residential construction. The metric equivalent is also written as 12.7 mm to be more precise. European drywall (plasterboard) is commonly sold in 12.5 mm thickness, which is essentially the same as the US ½ inch standard.

Drywall Guide: Sizes, Thickness, Coverage in Sq Ft & Sq M

Standard Drywall Sheet Sizes and Coverage

Drywall (also called gypsum board, wallboard, or plasterboard) is sold in 4-foot-wide sheets of varying lengths. The 4×8 sheet is the most common and accounts for most residential work. Longer sheets (4×10 and 4×12) reduce the number of butt joints on tall walls and ceilings.

Sheet Size	Coverage (sq ft)	Coverage (sq m)	Best Use
4 × 8 ft	32	2.97	Standard walls and ceilings (8 ft rooms)
4 × 9 ft	36	3.34	9 ft ceilings, reduces horizontal seam
4 × 10 ft	40	3.72	10 ft walls, commercial applications
4 × 12 ft	48	4.46	Tall ceilings, long wall runs, fewer seams

Drywall Thickness Options

Thickness (in)	Thickness (mm)	Type / Application
¼ in	6 mm	Curved surfaces, repair layer over existing drywall
&frac38; in	10 mm	Lightweight; less common, double-layer systems
½ in	12.7 mm	Standard — most interior walls and ceilings
&frac58; in	15.9 mm	Type X fire-rated — garages, stairwells, party walls

Estimating Sheets and Materials

The basic formula for sheets needed: Sheets = (Total wall area ÷ 32) + 10% waste

For a 12×12 room with 8 ft ceilings:

Perimeter = 48 ft × 8 ft ceiling = 384 sq ft of wall
Ceiling = 12 × 12 = 144 sq ft
Total area = 528 sq ft, minus ~60 sq ft for openings = 468 sq ft
Sheets = (468 ÷ 32) × 1.10 = 16.1 → buy 17 sheets

Beyond sheets, budget these additional materials per 4×8 sheet:

Screws: approximately 28–32 drywall screws per sheet (for 16-in stud spacing)
Joint compound: roughly 0.5 lb of all-purpose compound per sq ft of finished wall (all three coats combined)
Mesh or paper tape: approximately 1 linear foot of tape per linear foot of seam

Use our area converter to convert between sq ft and sq m when working with European specifications or international project plans.