Drywall Panel Calculator
Drywall sheets for a room, its walls, gables and ceiling, laid out horizontally and vertically with 4x8 to 4x16 panels, plus breakage and cost. How it works
Use the Drywall Panel Calculator
About the Drywall Panel Calculator
A 10 × 10 ft room with 9 ft walls needs 14 sheets of 4x8 drywall hung vertically, or 15 hung horizontally, so 16 with a 10% breakage allowance. The drywall calculator lays out each wall in 4 ft strips both ways, reuses offcuts across the room and keeps the layout with fewer panels. Doors and windows are not taken off the count, because sheets are hung over them and cut out. They only lower the area figure, at 3 × 7 ft per door and 4 × 4 ft per window unless you type other sizes. Gable ends and a price per panel can be added.
Drywall sheets for the walls of common rooms
| Room | 4x8 horizontal / vertical | 4x8 to buy | 4x12 horizontal / vertical | 4x12 to buy | 4x8 to buy with the ceiling |
|---|---|---|---|---|---|
| 10 × 10 ft, 8 ft walls | 10 / 12 | 11 | 8 / 12 | 9 | 16 |
| 10 × 12 ft, 8 ft walls | 11 / 12 | 13 | 8 / 12 | 9 | 17 |
| 12 × 12 ft, 8 ft walls | 12 / 12 | 14 | 8 / 12 | 9 | 19 |
| 12 × 14 ft, 8 ft walls | 14 / 14 | 16 | 9 / 14 | 10 | 22 |
| 12 × 16 ft, 8 ft walls | 14 / 14 | 16 | 10 / 14 | 11 | 22 |
| 10 × 10 ft, 9 ft walls | 15 / 14 | 16 | 12 / 12 | 14 | 20 |
| 12 × 12 ft, 9 ft walls | 18 / 14 | 16 | 12 / 12 | 14 | 20 |
| 14 × 16 ft, 9 ft walls | 24 / 18 | 20 | 15 / 16 | 17 | 29 |
| 12 × 12 ft, 10 ft walls | 18 / 15 | 17 | 12 / 12 | 14 | 22 |
To buy = the layout with fewer panels plus 10% for breakage, rounded up. The last column adds the ceiling. Doors and windows do not change these counts.
Frequently asked questions
- How many sheets of drywall do I need for a 12x12 room?
- With 8 ft walls, 12 sheets of 4x8 either way, or 14 with 10% for breakage. With 4x12 sheets hung horizontally it is 8, or 9 to buy. Boarding the ceiling too takes the 4x8 count to 19.
- Should drywall be hung horizontally or vertically?
- The calculator counts both and keeps the one with fewer panels. In a 10 × 10 ft room with 9 ft walls, 4x8 sheets take 15 horizontally and 14 vertically; with 8 ft walls horizontal wins, 10 against 12. It counts panels only and does not compare seams or finishing.
- Why doesn’t adding doors and windows lower the count?
- Sheets are hung over openings and cut out afterwards, and the cut-outs are rarely usable. The area figure does subtract them, at 21 sq ft a door and 16 sq ft a window unless you change the sizes: the 10 × 10 ft room with 9 ft walls, one door and two windows has 307 sq ft to cover, 10 panels by area alone, a lower bound no layout reaches.
- How many 4x12 sheets do I need instead of 4x8?
- In the 10 × 10 ft room with 9 ft walls, 12 sheets of 4x12 either way, 14 to buy with breakage, against 14 sheets of 4x8 and 16 to buy. Choose any panel from 4x8 to 4x16 and the calculator lays it out again.
- How do I count drywall for a gable wall?
- Enter the gable’s base and height and how many there are. Each is covered in 4 ft columns as tall as the triangle within each column, and the sloped offcuts join the same packing as the walls. Two gables 20 ft wide and 6 ft high add 120 sq ft: a 20 × 12 ft room with 8 ft walls goes from 16 sheets of 4x8 (18 to buy) to 22 (25 to buy).
- How many sheets of 1/2 inch or 5/8 inch drywall do I need?
- The same number either way. Thickness is not an input, because the count depends only on the sheet’s width and length and on the room. Pick the thickness your walls or ceiling call for, then use the count for that sheet size.
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