How many sheets of drywall do I need?
Measure the length and width of the room and the height of the walls. USG says to take off large openings such as doors and picture windows, but not small ones like outlet boxes. The calculator takes off 21 sq ft for each door and 15 sq ft for each window (Sherwin-Williams' estimating allowances), the same as our Paint Calculator.
USG's own estimates leave out waste, so the waste box starts at 0. Add some if you'll cut around a lot of corners or openings; it adds sheets, not screws or compound.
Source USG · Sheetrock Installation and Finishing Guide (J371) ↗USG · Sheetrock Wallboard Estimator ↗Sherwin-Williams · Painter Skills Program, Part 1 (slide 35) ↗
How to calculate drywall
Here it is with your numbers:
- Add up the four walls and multiply by the height: (12 + 12 + 12 + 12) × 8 = 384 sq ft.
- Take off 21 sq ft for each door and 15 for each window: 384 − (1 × 21) − (2 × 15) = 333 sq ft.
- Add the ceiling, length × width: 333 + (12 × 12) = 477 sq ft.
- Divide by the area of a 4 × 8 ft sheet (32 sq ft): 477 ÷ 32 = 14.9063 sheets, rounded to 14.91.
- Round up to whole sheets: 15 sheets.
It means buying 15 sheets of 4 × 8 ft drywall, 597 screws, 5 gallons of joint compound and 177 ft of tape.
Screws, joint compound and tape
USG's rates for each 1,000 sq ft of drywall, and what they come to for one sheet. The calculator rounds each one up, as USG's own estimator does.
| Material | Per 1,000 sq ft | Per 4 × 8 sheet |
|---|---|---|
| Type W screws | 1,250 | 40 |
| All Purpose joint compound | 10 gal | 0.32 gal |
| Joint tape | 370 ft | 11.84 ft |
Source USG · Sheetrock Paper Joint Tape data sheet (J1736) ↗
Drywall for common room sizes
Walls and ceiling, 8 ft high, with 1 door and 2 windows, no waste.
| Room | Area | 4 × 8 sheets |
|---|---|---|
| 10 × 10 ft | 369 sq ft | 12 |
| 12 × 10 ft | 421 sq ft | 14 |
| 12 × 12 ft | 477 sq ft | 15 |
| 14 × 12 ft | 533 sq ft | 17 |
| 16 × 12 ft | 589 sq ft | 19 |
| 16 × 14 ft | 653 sq ft | 21 |
| 20 × 16 ft | 845 sq ft | 27 |
FAQs
How many sheets of drywall do I need?
Add up the wall areas, take off doors and large windows, add the ceiling, then divide by the area of one sheet and round up. A 12 × 12 ft room with 8 ft walls, 1 door, 2 windows and the ceiling has 477 sq ft: 14.91 sheets of 4 × 8 ft, so buy 15.
Source USG · Sheetrock Installation and Finishing Guide (J371) ↗
How many screws per sheet of drywall?
USG's estimator allows 1,250 screws per 1,000 sq ft, which is 40 screws for a 4 × 8 ft sheet, 50 for 4 × 10 and 60 for 4 × 12. That is for screws spaced 12 in apart on ceilings and 16 in on walls.
How much mud per sheet of drywall?
USG allows 10 gallons of All Purpose joint compound per 1,000 sq ft of drywall, about 0.32 gallons for each 4 × 8 ft sheet. It covers the joints, inside corners and corner bead in a typical room; USG says coverage can vary widely with the walls and tools.
Source USG · Sheetrock Installation and Finishing Guide (J371) ↗
How big is a sheet of drywall?
USG's UltraLight panels are 4 ft wide (also 54 in) and 8 – 16 ft long. The 4 × 8, 4 × 10 and 4 × 12 ft sizes are the ones in USG's coverage table: 32, 40 and 48 sq ft a sheet.
Source USG · Sheetrock UltraLight Panels data sheet (WB2501) ↗
How much does a sheet of drywall weigh?
USG gives its 1/2 in UltraLight panels a nominal 1.25 lb per sq ft, so a 4 × 8 ft sheet weighs about 40 lb and a 4 × 12 ft sheet about 60 lb. Regular and fire-rated panels weigh more.
How thick is drywall?
USG makes its Sheetrock gypsum panels in four thicknesses: 5/8 in, 1/2 in, 3/8 in and 1/4 in. The 1/4 in panel is only for covering existing walls and ceilings, not as a single layer on its own.
Source USG · Sheetrock Installation and Finishing Guide (J371) ↗
Is Sheetrock the same as drywall?
Sheetrock is a brand of drywall: SHEETROCK is a trademark of USG for its gypsum panels and finishing products. Drywall, gypsum board and wallboard are the general names.
Source USG · Sheetrock Paper Joint Tape data sheet (J1736) ↗
How long does drywall mud take to dry?
USG's finishing steps say to let each coat dry overnight, and that drying time varies with temperature, humidity and job site conditions. A finish usually takes three coats over the tape.
Source USG · Sheetrock Installation and Finishing Guide (J371) ↗
Sources
- USG: Sheetrock Installation and Finishing Guide (J371)
- USG: Sheetrock Wallboard Estimator
- USG: Sheetrock Paper Joint Tape data sheet (J1736)
- USG: Sheetrock UltraLight Panels data sheet (WB2501)
- Sherwin-Williams: Painter Skills Program, Part 1 (slide 35)