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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