Use this drywall calculator, also called a sheetrock calculator, to find how many sheets of drywall you need for a room. Enter the room size and pick a sheet size. You also get the joint compound, tape and screws to buy, and a cost estimate if you add your prices.
Extra and cost
Mud and tape use typical maker figures: about 10 gallons of all-purpose compound and 370 ft of tape per 1,000 sq ft of board. Corner bead is extra.
How the drywall calculator works
- Wall area = 2 × (room length + room width) × wall height
- Openings: 21 sq ft is taken off for each door (3 × 7 ft) and 15 sq ft for each window (3 × 5 ft)
- Area to cover = wall area − openings + ceiling area (length × width)
- Sheets = area to cover × (1 + 10% extra) ÷ area of one sheet, rounded up
- Joint compound = about 10 gallons per 1,000 sq ft of board, sold in 4.5 gallon pails
- Joint tape = about 370 ft per 1,000 sq ft, sold in 250 ft rolls
- Screws = about 1 per sq ft on walls and 1.25 per sq ft on ceilings, plus the same 10% extra
The compound and tape figures are typical values printed by drywall makers. Real use depends on how many coats you apply and how wide you feather them.
Worked example
A 14 × 12 ft bedroom with 8 ft walls, one door and two windows, walls and ceiling, in 4 × 8 ft sheets:
- Walls: 2 × (14 + 12) × 8 = 416 sq ft
- Openings: 21 + 2 × 15 = 51 sq ft, so the walls need 365 sq ft
- Ceiling: 14 × 12 = 168 sq ft, so the total is 533 sq ft
- Sheets: 533 × 1.10 ÷ 32 = 18.3, rounded up to 19 sheets of 4 × 8 ft, or 13 sheets of 4 × 12 ft
- Joint compound: 533 ÷ 1,000 × 10 = 5.3 gallons, so 2 pails of 4.5 gallons
- Tape: 533 ÷ 1,000 × 370 = 197 ft, so 1 roll of 250 ft
- Screws: (365 × 1 + 168 × 1.25) × 1.10 = 633 screws
Sheets for common rooms
For 8 ft walls, walls and ceiling, one door and two windows, with 10% extra:
| Room | Area to cover | 4 × 8 ft sheets | 4 × 12 ft sheets |
|---|---|---|---|
| 10 × 10 ft | 369 sq ft | 13 | 9 |
| 10 × 12 ft | 421 sq ft | 15 | 10 |
| 12 × 12 ft | 477 sq ft | 17 | 11 |
| 14 × 12 ft | 533 sq ft | 19 | 13 |
| 16 × 14 ft | 653 sq ft | 23 | 15 |
| 20 × 16 ft | 845 sq ft | 30 | 20 |
Which drywall to use
| Type | Common use |
|---|---|
| ½ in regular | Most interior walls |
| ½ in sag-resistant or ⅝ in | Ceilings, especially with framing 24 in apart |
| ⅝ in fire-rated (Type X) | Garage walls and ceilings next to living space, where code calls for it |
| Moisture-resistant | Bathrooms and laundry rooms, away from direct water |
| Cement board | Behind tile in showers and tub surrounds |
Fire-rated board and where it goes are set by code, so follow common US code and check your local code.
Tips for hanging drywall
- Use the longest sheets you can carry. Fewer sheets means fewer seams to tape. A 4 × 12 ft sheet weighs around 70 to 80 lb at ½ in, so plan for two people.
- Hang the ceiling first, then the walls, with the top wall sheet tight to the ceiling.
- Check the framing before you order. Studs at 16 in apart suit ½ in board. The stud calculator counts the framing for a new wall.
- Stagger the end joints between rows, so seams don’t line up across the wall.
- Count outside corners and buy corner bead separately. It is sold in 8 and 10 ft lengths.
- When the walls are finished, the paint calculator works out primer and paint for the same room.
Frequently asked questions
How many sheets of drywall do I need?
Add up the wall and ceiling area, take off doors and windows, then divide by the area of one sheet. A 4 × 8 ft sheet covers 32 sq ft and a 4 × 12 ft sheet covers 48 sq ft. Add about 10% for cuts. A 12 × 12 ft room with 8 ft walls and a ceiling needs about 17 sheets of 4 × 8 ft.
How much drywall mud do I need?
About 10 gallons of all-purpose joint compound per 1,000 sq ft of drywall, which is a little over two 4.5 gallon pails. One pail covers roughly 450 sq ft. Heavy texture or a skim coat needs much more.
How much drywall tape do I need?
About 370 ft of tape per 1,000 sq ft of drywall. That is roughly 12 ft per 4 × 8 ft sheet, so a 250 ft roll covers about 20 sheets.
How many screws are in a sheet of drywall?
About 32 screws for a 4 × 8 ft sheet on a wall and about 40 on a ceiling, where screws are closer together. Screw spacing is set by code and the board maker, so follow common US code and check your local code.
How much does it cost to hang and finish drywall?
It depends on the board, the finish level and labor where you live, and prices vary a lot by region. Enter your prices per sheet, per pail and per roll, and a labor price per square foot from a local quote, to get a total.
Results are estimates for planning. Sheet sizes, compound coverage and labor vary, so confirm quantities with your supplier. See How We Calculate for the formulas we use.
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