How many drywall sheets do I need? How to use the calculator
- 1Choose a whole room or a single wall, then enter its length and height (and width for a room).
- 2Tick whether the ceiling is included — or, for a new partition wall, whether both faces are boarded.
- 3Enter doors and windows, then choose the sheet size you'll buy.
How to calculate drywall sheets (formula)
- 01Area = 2 × (length + width) × height + ceiling − doors − windows
- 02Sheets = area × (1 + extra %) ÷ sheet area, rounded up — for the walls and for the ceiling separately
- 03Screws = area × screws per area; compound = area × compound per area
- 04Tape = area × (1 ÷ sheet width + 1 ÷ sheet length) + inside corners
The extra covers offcuts around openings and the occasional broken corner. 10 % is common; rooms with many openings or angles need more.
Choose sheets as tall as your walls where you can — fewer horizontal joints means less taping and a better finish.
Every sheet edge meets the next sheet, so each sheet brings half its perimeter in joints: a 4 × 8 ft sheet has 12 ft of joint per 32 ft², which is 0.375 ft of tape per ft² (about 1.25 m per m² for 1200 × 2400 mm boards). The inside corners of the room are added on top.
Drywall calculation example
A 4 m × 3 m room with 2.4 m walls and the ceiling, less one door and one window, has 42.2 m² to cover.
With 10% extra and 2.88 m² sheets, you need 17 sheets.
Tips before you buy
- Use moisture-resistant board in bathrooms and fire-rated board where your building rules require it.
- Ceiling boards are heavy — use a board lifter or a second person.
- Screws, joint tape and compound are estimated with rules of thumb — use the figures on your boards' fixing guide and the compound's bag when they differ.
Frequently asked questions
What size is a sheet of drywall?
In the US, 4 × 8 ft (32 ft²) is standard, with 4 × 10 and 4 × 12 ft for taller walls. In the UK, 1200 × 2400 mm (2.88 m²) is most common; in France 1200 × 2500 mm, and in Germany boards are usually 1250 mm wide.
Should I subtract windows and doors?
Yes, but keep the 10 % extra — cutting around openings creates offcuts that are often too small to reuse.
How do I calculate how much drywall I need?
Add the wall areas (perimeter × height) and the ceiling, then divide by the area of one sheet. A 12 × 12 ft room with 8 ft walls has 48 × 8 = 384 ft² of wall and 144 ft² of ceiling: 528 ft² ÷ 32 ft² per 4 × 8 sheet = 16.5, so 17 sheets, or 19 with 10 % for cuts.
Sources
- Standard sheet sizes: US 4 × 8/10/12 ft; UK/EU 1200 × 2400/2700 mm.
- Gyprock Plus (Australia): 1200 and 1350 mm wide, 2400–6000 mm long
- Drywall sizes by country: US 48 and 54 in wide; Europe 1200 mm (also 600 and 900 mm) wide, up to 3 m and more — Wikipedia
- Screws about 1 per ft² and ready-mixed compound about 138 lb per 1,000 ft² (three coats): USG Gypsum Construction Handbook rules of thumb
Formulas last reviewed: September 30, 2026 ·How we check our formulas