How many sheets of drywall do I need?
Net area divided by sheet area, with the faces counted properly.
Divide the area to be boarded by the area of one sheet and add 10 % waste. A 4 x 8 ft sheet covers 32 sq ft; a stud partition is boarded on both faces.
The calculation
Common sheet sizes
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| Size | Area | Typical use |
|---|---|---|
| 4 x 8 ft | 32 sq ft | The US standard |
| 4 x 10 ft | 40 sq ft | 9 ft ceilings, fewer joints |
| 4 x 12 ft | 48 sq ft | Long walls, fewest butt joints |
| 1.20 x 2.50 m | 32.3 sq ft | European standard |
| 1.20 x 3.00 m | 38.8 sq ft | Taller European ceilings |
One face or two
This is the question that causes most errors. A stud partition (a framed wall separating two rooms) is boarded on both sides: it needs twice the sheets of the wall area. A dry lining (board fixed against an existing wall) takes board on one face only.
Choose the sheet length for your ceiling
If your ceiling is 8 ft 6 in and you buy 8 ft sheets, every wall needs a 6 in strip at the top: extra work and one more joint to tape. Measuring the height before choosing the format saves more time than any other trick.
What this calculation excludes
- Framing: studs at 16 or 24 in centres plus top and bottom track.
- Screws: roughly 25-30 per sheet.
- Tape and joint compound: calculated by linear feet of joint.
- Insulation: calculated by area, in its own calculator.
Waste
10 % for straight walls. 15 % for ceilings, where handling is harder and corners break more often, and for rooms with many openings, where offcuts do not get reused.
Sources and methodology
The calculation is area-based with a configurable waste factor. The sheet sizes listed are those commonly sold in the US and Europe.
Frequently asked questions
How many sheets of drywall do I need?
For a 12 x 12 ft room with an 8 ft ceiling, boarding one face, 13 sheets of 4 x 8 ft including 10 % waste. For a partition boarded both sides, 26.
What size is a sheet of drywall?
4 x 8 ft is the US standard (32 sq ft), with 4 x 10 and 4 x 12 also common. In Europe, 1.20 x 2.50 m.
Do both sides of a partition get boarded?
On a stud partition, yes: board goes on both faces. On a dry lining against an existing wall, one face only.
How many screws per sheet?
Roughly 25-30 per sheet depending on stud spacing. Not part of this calculation, but worth budgeting for.