How many sheets of drywall do I need?
The walls of a room are 2 x (length + width) x height. The ceiling is length x width. The area to cover is the walls plus the ceiling, less the doors and windows. Sheets = that area x (1 + the extra) / the area of one sheet, rounded up.
The formula
A sheet 4 ft by 8 ft is 4 x 8 = 32 square feet. Enter your own sheet's width and length under Sheet width and Sheet length.
We found no source for an extra on drywall, so Extra to order starts at 10 as an example. Ask your supplier or installer how much to add for cuts.
Worked example
A room 12 ft long and 10 ft wide with 8 ft walls. The walls are 2 x (12 + 10) x 8 = 352 square feet and the ceiling is 12 x 10 = 120 square feet, so 352 + 120 = 472 square feet with no openings. A sheet 4 ft by 8 ft is 32 square feet. With an example extra of 10%, 472 x 1.1 = 519.2 square feet, and 519.2 / 32 = 16.23, which rounds up to 17 sheets.
How many sheets of drywall for a 12x12 room?
Sheets for four example rooms with 8 ft walls and a ceiling, no openings, 4 x 8 ft sheets and an example extra of 10%. A 12 x 12 ft room takes 528 square feet, which is 19 sheets. The sizes are examples to show the sum.
| Room (ft) | Area (ft²) | Sheets before rounding | Sheets |
|---|---|---|---|
| 10 x 10 | 420 | 14.44 | 15 |
| 12 x 12 | 528 | 18.15 | 19 |
| 12 x 14 | 584 | 20.08 | 21 |
| 14 x 16 | 704 | 24.20 | 25 |
What size are sheets of drywall?
USG says its Sheetrock Brand MH UltraLight Panels Tuf-Base, a 1/2 in lightweight panel for manufactured housing, come 48 in wide in lengths of 8, 9, 10, 12, 14 and 16 ft, and 54 in wide in lengths of 12, 14 and 16 ft, and that other sizes are available by special order. [2] That is one maker's panel: other boards differ, so use the size on your sheet.
A 54 in sheet is 54 / 12 = 4.5 ft wide. [1] The area of a sheet is its width times its length.
| Sheet (ft) | Area (ft²) |
|---|---|
| 4 x 8 | 32 |
| 4 x 9 | 36 |
| 4 x 10 | 40 |
| 4 x 12 | 48 |
| 4 x 14 | 56 |
| 4 x 16 | 64 |
| 4.5 x 12 | 54 |
How many sheets of drywall for a whole house?
Run the calculator once for each room and add the sheets, or work out each room's area and add them. Enter the doors and windows of each room under Openings to take away.
We found no source for how much the offcuts of one room can be used in the next. Ask your installer before you reduce the order.
How much joint compound do I need?
We found no source for joint compound or tape coverage, so this calculator does not count them. The coverage is printed on the bucket or the box.
How much does drywall cost?
We state no price. Ask local suppliers for the price of one sheet, then enter it under Price per sheet, in the section Price (optional) above, to see the total. Labor is not counted. The site does not store the prices you type.
Common mistakes and limits
- Forgetting the ceiling. Pick Walls and ceiling, or Walls only, above the openings box.
- Mixing units. Enter the room and the sheet in feet and the openings in square feet.
- Taking away the openings twice. Enter each door and window once, as one total in square feet.
- What this tool does not cover: thickness, type of board, framing, tape, compound, screws and labor.
Frequently asked questions
How much drywall tape do I need?
We found no source we can cite for the length of tape per sheet or per square foot. Ask your supplier, or read the coverage on the package.
How much does it cost to drywall a room?
We state no price. Ask local suppliers for the price of one sheet, then enter it under Price (optional) above to see the total for the sheets to order. Labor is not counted.
How many square feet is a sheet of drywall?
Width times length: a 4 x 8 ft sheet is 32 square feet, a 4 x 10 ft sheet is 40 and a 4 x 12 ft sheet is 48.
How do I take away doors and windows?
Add the area of each door and window, in square feet, and enter the total under Openings to take away. A door 3 ft by 7 ft is 21 square feet.
How much extra drywall should I order?
We found no source we can cite for an extra on drywall, so the 10% on this page is an example. Ask your supplier or installer.
Sources and references
- National Institute of Standards and Technology (NIST). NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically (SP 811, accessed November 2026). Used for: the inch and foot relationship (a 54 inch sheet is 4.5 feet).
- USG Corporation. Sheetrock Brand MH UltraLight Panels Tuf-Base, product data (accessed November 2026). Used for: the widths and lengths of one maker's 1/2 inch panel.
How we use sources: methodology.
Estimates only. Confirm quantities with your supplier. See the disclaimer. Found a wrong result? Report an error.