Drywall Calculator
Calculate drywall sheets, joint compound, tape, and screws needed for your project. Supports 4x8, 4x10, and 4x12 sheets.
Project Area
Calculate: (Length × Width) for each wall/ceiling
Sheet Size
Standard: 10-15% for cuts and waste
Pricing (Optional)
Drywall Needed
18 sheets
4' × 8' drywall
How to Calculate Drywall for Your Project
Accurate drywall calculations prevent costly trips to the store and project delays. This calculator estimates sheets, joint compound (mud), tape, and screws needed for walls and ceilings.
Drywall Sheet Sizes
- 4' × 8' (32 sq ft): Standard size, easiest to handle, fits most rooms
- 4' × 10' (40 sq ft): Reduces seams on 9-10 ft walls
- 4' × 12' (48 sq ft): Best for ceilings and tall walls, fewer joints
Common Drywall Thicknesses
- 1/4\": Repairs, overlays, curved surfaces
- 3/8\": Repairs, two-layer applications
- 1/2\": Standard for walls and ceilings (most common)
- 5/8\": Fire-rated, soundproofing, commercial
Drywall Installation Formula
Sheets Needed = (Total Sq Ft ÷ Sheet Size) × (1 + Waste %)
Example: 500 sq ft ÷ 32 = 15.6 sheets × 1.15 = 17.9, round to 18 sheets
Joint Compound (Mud) Calculation
Estimate 0.053 lbs per square foot of drywall for all coats (taping, second coat, finish coat):
- 5-gallon bucket: Covers 400-500 sq ft (60 lbs)
- 4.5-gallon bucket: Covers 360-450 sq ft (54 lbs)
- 1-gallon box: Covers 80-100 sq ft (12 lbs)
Drywall Tape Requirements
Estimate 370 linear feet of tape per 1,000 square feet of drywall. This accounts for all seams, corners, and butt joints.
- Paper tape: Stronger, requires embedding compound
- Mesh tape: Self-adhesive, easier for DIY, slightly weaker
Drywall Screws
Use 1 lb of screws per 4-5 sheets of drywall. Space screws 12\" apart on walls, 12\" on ceilings. Use coarse-thread screws for wood studs, fine-thread for metal studs.
Hanging Direction
- Walls: Hang horizontally for fewer seams and stronger joints
- Ceilings: Perpendicular to joists for maximum support
- Tall Walls: Use longer sheets to minimize horizontal seams
Important Notes
Always add 10-15% waste for cuts, mistakes, and damaged sheets. Complex layouts with many openings (windows, doors) may require 20% waste.
Drywall installation costs $1.50-$3.00 per square foot professionally installed, including taping, mudding, and sanding.
Moisture-resistant (green board) or mold-resistant (purple board) drywall should be used in bathrooms, kitchens, and laundry rooms.
Frequently Asked Questions
How many sheets of drywall do I need?
Divide total square footage by 32 (for 4x8 sheets), 40 (for 4x10), or 48 (for 4x12). Add 10-15% waste. Example: 500 sq ft ÷ 32 = 15.6 sheets, round to 17-18 sheets with waste factor.
What size drywall should I use?
4x8 sheets (32 sq ft) are standard and easiest to handle. Use 4x10 or 4x12 for walls over 8 feet tall to reduce horizontal seams. Ceilings benefit from 4x12 sheets for fewer joints and stronger spans.
How much joint compound do I need?
Estimate 0.053 lbs of joint compound per square foot of drywall for all three coats. A 500 sq ft room needs about 27 lbs of mud. One 5-gallon bucket (60 lbs) covers 400-500 sq ft.
How much does drywall cost?
Drywall sheets cost $10-$20 each in Canada. Standard 4x8 sheets of 1/2\" drywall average $12-15. Specialty boards like moisture-resistant (green board) or fire-rated cost $15-$25 per sheet.
Do I hang drywall vertically or horizontally?
Hang horizontally on walls for stronger joints, better load distribution, and fewer seams. Ceilings should always hang perpendicular to joists. Vertical hanging is acceptable for walls under 8 feet or when using 4x12 sheets on tall walls.