Drywall (Sheetrock) Calculator
Enter the room size and choose a sheet size. You'll get sheet count with waste, plus finishing materials based on standard estimating rates.
- Tested formulas
- Feet or metric
- Printable shopping list
2 What to buy
Updates as you type| Wall area | 384 sq ft |
|---|---|
| Ceiling area | 144 sq ft |
| Openings deducted (half their area) | 18 sq ft |
| Board purchased | 576 sq ft |
| Paper tape | 213 ft → 1 × 250 ft roll |
| Drywall screws | ≈ 576 (2 lb of 1-1/4" coarse thread) |
Shopping list
Quick answer
A 12 × 12 ft room with 8 ft walls, including the ceiling, needs 18 sheets of 4 × 8 drywall with 10% waste, 2 buckets of joint compound and about 213 ft of tape.
Drywall sheets for common rooms
| Room | 4×8 sheets | 4×12 sheets | Joint compound |
|---|---|---|---|
| 10 × 10 ft | 14 | 10 | 1 buckets |
| 10 × 12 ft | 16 | 11 | 2 buckets |
| 12 × 12 ft | 18 | 12 | 2 buckets |
| 12 × 14 ft | 20 | 13 | 2 buckets |
| 14 × 16 ft | 24 | 16 | 2 buckets |
| 16 × 20 ft | 31 | 21 | 3 buckets |
8 ft walls plus ceiling, one door, one window, 10% waste. Use the calculator above for your exact size.
How many sheets of drywall?
Add up the wall area (perimeter × height) and the ceiling area if you're doing it, add a waste allowance, and divide by the sheet area: 32 sq ft for a 4×8 sheet, 40 for 4×10 and 48 for 4×12. We only deduct half the area of doors and windows. The cut-outs are rarely usable, and cutting around openings creates extra waste.
Worked example: 12 × 12 ft room, 8 ft walls, with ceiling
- Walls 384 sq ft + ceiling 144 sq ft − openings 17.5 = 510.5 sq ft
- +10% ÷ 32 = 18 sheets of 4×8
- Finishing: 2 buckets of joint compound, 1 roll of tape, about 576 screws
Which sheet size?
4×8 sheets are easiest to carry and the only practical choice for one person. 4×12 sheets mean fewer seams, so less taping and a better finish, but they need two people and won't fit up most stairways. Hanging sheets horizontally on walls is standard: it puts the tapered seam at a comfortable height and reduces total seam length.
Thickness
- ½": standard for walls.
- ⅝" Type X: fire-rated. Required on walls between an attached garage and the house, and common on ceilings.
- Moisture-resistant board for bathrooms and laundry rooms. Use cement board behind tile in showers.
Frequently asked questions
How many sheets of drywall for a 12×12 room?
Walls only, with 8 ft ceilings, 12 sheets of 4×8 plus waste. Including the ceiling, about 18 sheets.
How much joint compound do I need?
Roughly 140 lb of ready-mixed compound per 1,000 sq ft of drywall, about two 4.5-gallon buckets for three coats.
How many screws per sheet of drywall?
About 32 for a 4×8 sheet on walls (studs 16" o.c., screws every 16") and more on ceilings, where screws go every 12".
Last reviewed 2026-10-21. See how we calculate for our sources and assumptions.