Drywall sheets by room size
Walls and ceiling of one room with 8 ft walls, including 10% extra.
| Room | Walls + ceiling (sq ft) | 4×8 sheets | 4×12 sheets | 4.5 gal pails of mud |
|---|---|---|---|---|
| 10 × 10 ft | 420 | 15 | 10 | 1 |
| 10 × 12 ft | 472 | 17 | 11 | 2 |
| 12 × 12 ft | 528 | 19 | 13 | 2 |
| 12 × 14 ft | 584 | 21 | 14 | 2 |
| 14 × 16 ft | 704 | 25 | 17 | 2 |
| 16 × 20 ft | 896 | 31 | 21 | 2 |
How the drywall calculator works
Wall area = 2 × (length + width) × height
Ceiling area = length × width
Sheets = total area × (1 + waste %) ÷ sheet area, rounded up
Joint compound = area × 10 gal ÷ 1,000 sq ft
Tape = area × 370 ft ÷ 1,000 sq ft · Screws ≈ area × 1,000 ÷ 1,000 sq ft
Example
A 12 × 12 ft room with 8 ft walls and a ceiling is 384 + 144 = 528 sq ft. With 10% extra, 580.8 ÷ 32 = 18.2, so 19 sheets of 4 × 8.
Finishing supplies
Supply quantities come from USG's Sheetrock installation guide, which lists about 10 gallons of all-purpose joint compound and 370 ft of paper tape per 1,000 sq ft of panels, and from USG's construction handbook, which estimates roughly 1,000 screws per 1,000 sq ft at 16 in framing. The calculator converts these to 4.5-gallon pails, 500 ft rolls and boxes of screws at about 238 screws per pound.
Choosing between sizes and thicknesses? See drywall sizes and how many sheets you need.
Not included
Corner bead, primer, sanding supplies and moisture- or fire-rated panels for bathrooms, garages and ceilings where code requires them are not counted. Check local code for fire-rated drywall between a garage and living space.
Frequently asked questions
How many sheets of drywall do I need for a 12×12 room?
A 12 × 12 ft room with 8 ft walls has 384 sq ft of wall and 144 sq ft of ceiling, 528 sq ft in all. With 10% extra that is 580.8 sq ft, or 19 sheets of 4 × 8 drywall (13 sheets of 4 × 12). Walls only: 14 sheets of 4 × 8.
Should I subtract doors and windows when estimating drywall?
Most estimators don't, and neither does this calculator. Sheets are usually hung across openings and the hole is cut out afterward, and the offcuts are rarely big enough to reuse. The 10% allowance covers normal cutting waste; skip it only for very simple rooms with no openings.
How much joint compound do I need?
USG's installation guide estimates about 10 gallons of all-purpose joint compound per 1,000 sq ft of drywall, or about 9 gallons of lightweight compound. For a 528 sq ft room that is about 5.3 gallons, or two 4.5-gallon pails.
How many drywall screws do I need?
USG's handbook estimates roughly 1,000 screws per 1,000 sq ft of board when framing is 16 in on center, with screws no more than 16 in apart on walls and 12 in on ceilings. A 1 lb box of #6 × 1¼ in coarse-thread screws holds about 238, so a 528 sq ft room needs about 2.2 lb.
Should I use 4×8 or 4×12 drywall sheets?
Longer 4 × 12 sheets mean fewer butt joints to tape and finish, which saves time and gives a flatter wall, especially on long walls and ceilings. They are heavy and awkward, though, and harder to get up stairs or into small rooms. 4 × 8 sheets are easier for one person to handle.
Sources
Prices are national shelf prices and cost-guide ranges read on September 17, 2026. The calculator uses the typical price (the median of the shelf prices we saw) and shows the low–high range; type your own local price to update the total.
All sources for this page (13)
Coverage, yield and building specs
- USG Sheetrock Gypsum Panels Installation Guide J371 — fastener/compound/tape calculator accessed 2026-09-17
- USG Sheetrock All Purpose Joint Compound submittal J1969 accessed 2026-09-16
- CGC (USG Canada) Gypsum Construction Handbook, ch. 3 accessed 2026-09-16
- Inch Calculator — Drywall calculator accessed 2026-09-16
- Omni Calculator — Drywall calculator accessed 2026-09-16
Prices
- The Home Depot — Drywall sheets category accessed 2026-09-16
- HomeGuide — Sheetrock & drywall prices accessed 2026-09-16 · page dated 2025-06-26
- DrywallInstallationCost.com — Drywall materials cost accessed 2026-09-16 · page dated 2026-04-27
- The Home Depot — USG Sheetrock joint compound accessed 2026-09-16
- Ace Hardware — USG All Purpose joint compound 4.5 gal accessed 2026-09-16
- The Home Depot — Paper drywall tape accessed 2026-09-16
- The Home Depot — Grip-Rite #6 x 1-1/4 in. drywall screws 5 lb accessed 2026-09-16
- The Home Depot — Grip-Rite #6 x 1-1/4 in. drywall screws 1 lb accessed 2026-09-16
Estimates for planning purposes only, not professional construction advice. Check local building codes and your product's instructions before you build. Prices are national averages collected from public retail listings and cost guides and will differ in your area. BuildHowMuch is independent and not affiliated with, endorsed by or paid by any retailer or manufacturer mentioned on this page. Nothing you enter is stored or sent anywhere.