How Much Drywall Do I Need? (Sheets & Supplies)
To calculate drywall, find the total wall area (perimeter × height) plus the ceiling if covering it, add 10% for waste, and divide by the sheet size (32 sq ft for a 4×8 sheet). A 14×12 ft room with 8 ft walls and a ceiling needs about 21 sheets, plus joint compound, tape, and screws.
Drywall is cheap per sheet but awkward to shop for twice, so a good estimate saves you a second trip and the hassle of returning surplus. The count depends on your room's wall and ceiling area, the sheet size you choose, and a small waste allowance for cuts around doors, windows, and outlets.
This guide shows how to calculate the number of drywall sheets you need, plus the joint compound, tape, and screws to finish the job — with a worked example you can follow for your own room.
Key takeaways
- Sheets = (wall area + ceiling area) × 1.10 ÷ sheet size.
- A 4×8 sheet covers 32 ft²; 4×10 covers 40; 4×12 covers 48.
- Add about 10% for waste and cuts.
- Budget ~1 screw per ft² and one compound bucket per ~12 sheets.
- Bigger sheets mean fewer seams to tape but are heavier to lift.
Skip the math
Get instant numbers with the Drywall Calculator.
How to calculate drywall sheets
Add up the wall area (the room's perimeter × ceiling height) plus the ceiling area if you're covering it. Add 10% for waste, then divide by the coverage of your chosen sheet size. For a 14 × 12 ft room with 8 ft ceilings: walls are (14+12) × 2 × 8 = 416 ft², the ceiling is 168 ft², totaling 584 ft². Add 10% (≈642 ft²) and divide by 32 for 4×8 sheets ≈ 21 sheets.
Drywall sheet sizes
| Sheet size | Coverage | Best for |
|---|---|---|
| 4 × 8 ft | 32 ft² | Easiest to handle, DIY |
| 4 × 10 ft | 40 ft² | Fewer seams on tall walls |
| 4 × 12 ft | 48 ft² | Fewest seams, needs helpers |
Finishing supplies you'll need
- Joint compound: about one 5-gallon bucket per 12 sheets.
- Drywall tape: roughly 0.39 linear ft per ft² of drywall.
- Screws: about one per square foot (roughly 1 lb per 5 sheets).
- Corner bead for every outside corner, plus a sanding sponge or pole sander.