Drywall Calculator
Estimate drywall sheets, joint compound, tape, screws, and material cost for walls, ceilings, rooms, basements, garages, and renovation projects.
Room dimensions
Enter your room size, sheet size, waste, and optional material prices.
How to Use the Drywall Calculator
Enter the length, width, and height of the room. The calculator estimates the wall area, subtracts standard door and window openings, adds the ceiling if selected, and divides the final area by your selected drywall sheet size. It also estimates joint compound, tape, screws, and optional material cost.
Common Drywall Sheet Sizes
| Sheet Size | Coverage | Best Used For |
|---|---|---|
| 4 × 8 ft | 32 sq ft | Small rooms, repairs, easier handling |
| 4 × 10 ft | 40 sq ft | Taller walls and fewer seams |
| 4 × 12 ft | 48 sq ft | Larger rooms and longer wall runs |
Example Drywall Estimate
For a 20 ft by 15 ft room with 8 ft walls, the wall area is about 560 square feet. After subtracting one standard door and two standard windows, the drywall area is about 509 square feet. With 10% waste, that becomes about 560 square feet, which requires roughly 18 standard 4 × 8 sheets.
Should You Add Extra Drywall?
Yes. Most drywall jobs should include 10–15% extra material. Extra sheets help cover cuts, broken corners, measurement errors, damaged panels, and odd wall shapes. Larger or more complex rooms may need a higher waste allowance.
Frequently Asked Questions
How do I calculate how many drywall sheets I need?
Find the drywall area by calculating wall area, subtracting openings, adding ceiling area if needed, and adding waste. Then divide by the square footage of one drywall sheet.
How much does a 4 × 8 drywall sheet cover?
A standard 4 × 8 drywall sheet covers 32 square feet.
How much drywall waste should I add?
A 10–15% waste allowance is common for drywall projects. Use more for rooms with many corners, closets, cuts, or unusual shapes.
Does this calculator include joint compound and tape?
Yes. The calculator provides rough estimates for joint compound, drywall tape, and screws based on the estimated drywall area and sheet count.