Calculator
Engineering
MathDrywall Calculator
Free online drywall calculator to estimate the number of drywall sheets, screws, joint compound, and tape needed for walls and ceilings. Calculate based on room dimensions with waste factor included.
What is a Drywall Calculator?
A Drywall Calculator is an essential tool for construction and renovation projects that estimates the quantity of drywall sheets (also known as sheetrock or gypsum board) and related materials needed to cover walls and ceilings. By entering room dimensions, sheet size, and waste factor, you can accurately determine how many sheets to purchase, along with the amounts of screws, tape, and joint compound required to complete the job.
How to Use the Drywall Calculator
- Enter the room length, width, and wall height in your preferred unit
- Check 'Include Ceiling' if you need to cover the ceiling as well
- Select the drywall sheet size you plan to use (standard is 4'×8' or 1.2m×2.4m)
- Choose a waste factor percentage (10% is standard for most projects)
- Optionally enter the number of doors and windows to subtract their areas
- Click Calculate to see the number of sheets and materials needed
Drywall Calculation Formulas
1. Wall Area = 2 × (Length + Width) × Height
2. Ceiling Area = Length × Width
3. Total Area = Wall Area + Ceiling Area (if included) - Exclusions
4. Sheets Needed = (Total Area × (1 + Waste Factor)) / Sheet Area
Material Estimates
Screws: ~1,000 screws per 1,000 ft² (or 100 m²)
Tape: ~370 ft per 1,000 ft² of drywall (or 1.2 m per m²)
Joint Compound: ~0.05 gallons per ft² (or 0.2 L per m²)
Tips for Accurate Drywall Estimation
- Always add waste factor to account for cuts, mistakes, and odd angles
- Standard drywall sheets are 4'×8' (32 ft²) for walls and 4'×12' for ceilings
- Hang drywall horizontally on walls less than 9 feet tall
- For rooms with many corners and angles, increase waste factor to 15-20%
- One screw every 8-12 inches along studs and edges
- Budget for 3 coats of joint compound (base, finish, and skim)
- Buy a few extra sheets - returns are easier than running short mid-project
About Drywall
Drywall, also known as gypsum board, wallboard, or sheetrock, is a panel made of calcium sulfate dihydrate (gypsum) compressed between two thick sheets of paper. It's the standard material for interior walls and ceilings in modern construction. Standard thickness is 1/2 inch for walls and 5/8 inch for ceilings or fire-rated walls. Drywall comes in various sizes, with 4'×8' being the most common. It's favored for its fire resistance, sound dampening properties, ease of installation, and smooth finish for painting or wallpapering.
Common Drywall Estimation Mistakes
- Not adding enough waste factor for cuts and mistakes
- Forgetting to account for ceiling area
- Using wrong sheet size for height of walls
- Not considering vertical vs horizontal hanging
- Underestimating joint compound and tape needed
- Ignoring odd angles and corners that create waste