How many sheets of drywall do I need for a 12x12 room?

A 12×12 room with 8-foot ceilings and 2 doors and 2 windows needs approximately 18-20 sheets of 4×8 drywall for walls and ceiling, including 10% waste. Without ceiling, you need about 12-14 sheets.

How many screws do I need per sheet of drywall?

Plan for about 32 screws per 4×8 sheet of drywall. Screws should be placed every 12 inches along edges and every 16 inches in the field (center of the sheet). That works out to roughly 1 pound of drywall screws per 5 sheets.

How much joint compound do I need?

Plan for about 1 gallon of joint compound per 100 square feet of drywall, which accounts for three coats (tape coat, fill coat, and finish coat). A 4.5-gallon bucket covers roughly 450 square feet.

How Much Drywall Do I Need?

February 19, 2026 · By DIY Calc

Quick answer: Calculate total wall area (perimeter × height), subtract doors (21 sq ft each) and windows (15 sq ft each), add ceiling if needed, then divide by 32 (the area of one 4×8 sheet). Add 10% for waste. A standard 12×12 room with 8-foot ceilings needs about 18 sheets including ceiling.

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The Step-by-Step Formula

Calculate wall area: Perimeter (2 × length + 2 × width) × ceiling height
Subtract openings: Standard door = 21 sq ft, standard window = 15 sq ft
Add ceiling: Length × width (if applicable)
Divide by 32: Each 4×8 sheet = 32 sq ft
Add 10% waste: For cuts, damaged sheets, and mistakes

Example: 12×14 Room, 8ft Ceilings, 1 Door, 2 Windows

Perimeter: 2(12 + 14) = 52 ft
Wall area: 52 × 8 = 416 sq ft
Subtract openings: 416 - 21 - 30 = 365 sq ft
Ceiling: 12 × 14 = 168 sq ft
Total: 365 + 168 = 533 sq ft
Sheets: 533 ÷ 32 = 16.7 → 17 sheets
With 10% waste: 19 sheets

Beyond Sheets: The Full Materials List

Sheets are just the start. Here's everything you need for a complete drywall job:

Drywall Screws

Use 1-1/4" coarse-thread drywall screws for 1/2" drywall on wood studs. Plan for about 32 screws per sheet, that's screws every 12" along edges and 16" in the field. One pound contains about 150 screws, so a typical room needs 3–5 pounds.

Joint Tape

Budget roughly 12 feet of tape per sheet of drywall. A standard roll is 75 feet. Paper tape is stronger for corners; mesh tape is easier for flat seams but requires setting-type compound for the first coat.

Joint Compound (Mud)

The biggest variable in drywall finishing. Plan for approximately 1 gallon per 100 square feet for three coats. A 4.5-gallon bucket covers about 450 sq ft. First-timers should buy an extra bucket, you'll sand through some spots and need to recoat.

Corner Bead

Every outside corner needs corner bead. Measure the height of each outside corner and buy 8-foot or 10-foot sticks. Paper-faced corner bead is easier to finish than metal for beginners.

Choosing the Right Drywall

Regular (white): Standard 1/2" for most walls and ceilings
Moisture-resistant (green board): For bathrooms and laundry rooms, NOT for direct water exposure
Mold-resistant (purple): Fiberglass-faced for high-humidity areas
Fire-rated (Type X): 5/8" thick, required for garage-to-house walls and some ceilings
Lightweight: About 25% lighter than standard, much easier to handle for ceiling installation

Tips for First-Timers

Hang ceilings first, then walls. Wall sheets support the ceiling edges.
Stagger seams, never align joints on adjacent sheets.
Don't over-drive screws, the paper face should dimple slightly, not break through.
Three thin coats of mud beat one thick coat every time.
Sand between coats with 120-grit, then finish with 150-grit.
Use a bright work light held at an angle to spot imperfections before painting.

Cost Estimates

Here's what to budget per sheet of 4×8 1/2" drywall:

Regular: $10–$15 per sheet
Moisture-resistant: $14–$18 per sheet
Fire-rated: $13–$17 per sheet

For a complete 12×12 room (walls + ceiling), expect to spend $250–$400 on all materials including sheets, screws, tape, mud, and corner bead.

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