Drywall Calculator
Sheets, mud, tape, and screws for any room — sized to 4×8, 4×10, or 4×12 boards with waste built in, so the truck comes back empty.
Counted at 20 sq ft each.
Counted at 15 sq ft each.
Add wall and ceiling areas for all rooms and enter the total.
You need
Enter dimensions
| Finishing supplies | Amount |
|---|---|
| Screws (1¼″ coarse) | — |
| Joint compound | — |
| Joint tape (500 ft rolls) | — |
½″ 4×8 sheets commonly run $12–$18.
How to Calculate Drywall
Drywall is estimated by surface area ÷ sheet size, then finishing supplies scale off the same area:
- Wall area: room perimeter × wall height, minus about 20 sq ft per door and 15 per window.
- Ceiling area: length × width, if you're hanging it.
- Sheets: total area ÷ sheet size (32, 40, or 48 sq ft), plus 10% waste, rounded up.
- Supplies: ~32 screws per 4×8 sheet, ~0.053 lb of compound per sq ft, ~370 ft of tape per 1,000 sq ft.
Drywall formulas
Sheets = (area × 1.10) ÷ sheet sq ft, rounded up
Compound (lb) = area × 0.053 · Tape (ft) = area × 0.37
Worked example — 12 × 12 room, 8″ walls, walls only: 384 − 35 = 349 sq ft × 1.10 = 384 sq ft ÷ 32 = 12 sheets of 4×8, ~384 screws, ~21 lb of compound, and 142 ft of tape.
Sheets Needed for Common Rooms
4×8 sheets, 8 ft walls, one door and one window, 10% waste:
| Room | Walls only | Walls + ceiling |
|---|---|---|
| 10 × 10 ft | 10 sheets | 14 sheets |
| 12 × 12 ft | 12 sheets | 17 sheets |
| 12 × 16 ft | 15 sheets | 21 sheets |
| 16 × 20 ft | 19 sheets | 30 sheets |
Which Drywall to Buy
- ½″ regular — the standard for walls and ceilings on 16″ framing.
- ⅝″ Type X — fire-rated; required on garage walls adjoining living space, and stiffer for 24″ ceiling framing.
- Moisture-resistant (green/purple) — bathrooms and laundry walls outside the wet zone; use cement board inside showers.
- Longer sheets = fewer joints. Every joint you don't hang is a joint you don't tape, mud, and sand — hang 4×12 where access allows.
Tips Before You Hang
- Hang ceilings first — wall sheets then support the ceiling edges.
- Horizontal on walls — it bridges more studs and puts the joint at a comfortable taping height.
- Screws just dimple the paper — a broken paper face holds nothing; set your drill's clutch.
- Buy mud in buckets for big jobs, boxes for small — an unopened box keeps; a part-used bucket eventually molds.
Frequently Asked Questions
How many sheets for a 12×12 room?
12 sheets of 4×8 for walls only (349 sq ft + 10%); 17 including the ceiling.
How many screws per sheet?
About 32 per 4×8 sheet at 16″ stud spacing — one per square foot. A pound of screws ≈ 200 ≈ six sheets.
How much mud per square foot?
About 0.053 lb per sq ft for a three-coat finish — one 4.5-gal bucket per ~450–475 sq ft.
How much tape?
About 370 ft per 1,000 sq ft — one 500 ft roll per average room.
4×8 or 4×12 sheets?
4×12 where walls are long and access allows (fewer joints); 4×8 for solo work and tight stairways.
What thickness?
½″ standard; ⅝″ Type X for garages and 24″ ceiling framing; moisture-resistant for damp rooms.
References
- USG — Gypsum Construction Handbook (estimating factors): usg.com
- Gypsum Association — application and finishing standards (GA-216): gypsum.org
- National Gypsum — installation guides: nationalgypsum.com