Drywall Calculator
Free and simple, type your room size and ceiling height and get how many drywall sheets to buy for the walls (and the ceiling, if you want it). No sign-up, no email.
Drywall: Calculate
Tip: sheets break and cuts go wrong, most people add 1 or 2 spares with the spare-sheets option above. Shops usually take back unopened, undamaged sheets.
How to Use: 3 Easy Steps
Step 1: Measure your room: length, width, and the ceiling height in feet.
Step 2: Choose if the ceiling is also being drywalled, and pick your sheet size (4 × 8 ft is the most common).
Step 3: Press Calculate. You get the number of sheets to buy.
Drywall Formula: How to Calculate How Many Sheets You Need
Walls: 2 × Ceiling Height × (Length + Width). Example for a 12 × 12 ft room with an 8 ft ceiling: 2 × 8 × 24 = 384 sq ft of wall.
Ceiling: Length × Width = 12 × 12 = 144 sq ft. Total = 384 + 144 = 528 sq ft.
Sheets: Total ÷ sq ft in one sheet, rounded up. Example: 528 ÷ 32 = 16.5, so buy 17 sheets of 4 × 8 ft.
Ready Answers for Common Rooms (8 ft ceiling, ceiling included, 4 × 8 ft sheets)
| Room | Total Area | Sheets to Buy |
|---|---|---|
| 10 × 10 ft | 420 sq ft | 14 sheets |
| 12 × 10 ft | 472 sq ft | 15 sheets |
| 12 × 12 ft | 528 sq ft | 17 sheets |
| 15 × 15 ft | 705 sq ft | 23 sheets |
| 20 × 20 ft | 1,040 sq ft | 33 sheets |
Doors and windows are not subtracted, in real jobs the cut pieces and offcuts around them use up about the same amount, which is how the pros estimate too.
Common Mistakes to Avoid
1. Forgetting the ceiling. The ceiling of a 12 × 12 room is 144 sq ft, that is 4 to 5 extra sheets. Decide first if the ceiling is included.
2. Buying the exact number. Sheets break and get cut wrong. Add 1 or 2 spare sheets to be safe, shops usually take back unopened, undamaged sheets.
3. Picking 4 × 12 sheets alone. They give fewer seams but are heavy and hard to move in a normal house. Most home jobs use 4 × 8.
4. Subtracting every door and window on paper. It looks clever but the offcuts waste about the same area. The standard way is to not subtract them.
Questions People Ask
How many drywall sheets do I need for a 12×12 room?
With an 8 ft ceiling and the ceiling included: 17 sheets of 4 × 8 ft. Walls only: 12 sheets.
Does this calculator subtract doors and windows?
No, and that is on purpose. The pieces cut around doors and windows waste about as much as the opening saves, so the pros estimate the full wall.
4 × 8 or 4 × 12 ft sheets, which is better?
4 × 12 sheets mean fewer seams to tape, but they are heavy and hard to carry through a house. Most homeowners use 4 × 8.
What else do I need besides sheets?
Screws, joint tape, and joint compound (mud). This calculator counts sheets and their cost only.
Can I use this for a garage or basement?
Yes. Measure it like any room. For a garage, walls only (no ceiling) is a common choice.
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