Drywall Calculator
Calculate the number of sheets, joint compound, tape, and screws needed for any room.
Room Dimensions
Settings
Estimation Results
Total Wall Area0 sq ft
Paintable Area (minus doors/windows)0 sq ft
Drywall Sheets (4×8 ft)0 sheets
Joint Compound0 gal
Drywall Tape0 ft
Drywall Screws0 screws
For estimation purposes only. Actual material needs may vary based on room layout. Consult a licensed contractor for exact quantities.
How This Calculator Works
The drywall calculator determines the total square footage of your walls (and optional ceiling) by multiplying the perimeter of the room by the ceiling height. It then subtracts the area of standard doors (21 sq ft) and windows (12 sq ft).
The formula for sheets is: Total Paintable Area ÷ 32 (sq ft per 4x8 sheet). We then apply a standard 10% waste factor to ensure you have enough material to account for cutoffs.
Example Calculation
For a 12x14 foot room with 8-foot ceilings, 1 door, and 2 windows:
- Wall Perimeter: 12 + 12 + 14 + 14 = 52 feet
- Gross Wall Area: 52 × 8 = 416 sq ft
- Deductions: 21 (1 door) + 24 (2 windows) = 45 sq ft
- Net Area: 416 - 45 = 371 sq ft
- Sheets Required: 371 ÷ 32 = 11.59 sheets
- With 10% waste: 11.59 × 1.1 = 12.75 sheets (round to 13)
Common Room Sizes (Walls Only, 8ft Ceilings)
| Room Size | Square Footage | 4x8 Sheets Needed |
|---|---|---|
| 10' × 10' | 320 sq ft | 11 sheets |
| 12' × 12' | 384 sq ft | 13 sheets |
| 12' × 15' | 432 sq ft | 15 sheets |
| 15' × 20' | 560 sq ft | 19 sheets |
Drywall FAQs
How many sheets of drywall do I need for a 12x12 room?
For a standard 12x12 room with 8-foot ceilings, you will need approximately 12 sheets of 4x8 drywall for the walls. If you are also doing the ceiling, add 5 more sheets. This assumes 1 door and 2 windows.
How much joint compound (mud) per sheet of drywall?
You generally need 0.053 gallons of joint compound per square foot of drywall. For a standard 4x8 sheet (32 sq ft), that equals about 1.7 gallons of mud. A 5-gallon bucket covers about 3 sheets.
How many screws per sheet of drywall?
A standard 4x8 sheet of drywall requires approximately 28 to 32 screws if studs are 16 inches on center. You'll need about 1 pound of screws for every 10 sheets.
How much drywall tape do I need?
You will need about 16 to 18 feet of drywall tape per 4x8 sheet. A standard 250-foot roll of tape will cover about 14 sheets.
Should I deduct doors and windows?
Yes, but you still need a waste factor. A standard door is about 21 sq ft and a standard window is 12 sq ft. Our calculator automatically subtracts this area, but adds a 10% waste factor to ensure you have enough material to make full cuts.