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FREE WASTE GUIDE FOR DRYLINING CONTRACTORS

How many sheets of plasterboard do I need?

Work out the area of every face you're boarding, take off the doors and windows, add a waste allowance, then divide by the area of one sheet. Round up to whole sheets.

A standard 2400 x 1200mm sheet covers 2.88m². So a wall face of 11m² after openings needs four sheets before waste, and five once you add it.

This page gives the common UK sheet sizes, the method step by step and a worked example.

Plasterboard sheet sizes and coverage

The most common sizes for 12.5mm wallboard in the UK:

  • 2400 x 1200mm: 2.88m² per sheet

  • 2700 x 1200mm: 3.24m² per sheet

  • 3000 x 1200mm: 3.60m² per sheet

  • 3600 x 1200mm: 4.32m² per sheet

  • 1800 x 900mm: 1.62m² per sheet

Pick a length that matches your wall height where you can. A 2700mm sheet on a 2.7m wall goes up in one piece, with no horizontal joint and less cutting.

Check the sizes your supplier stocks before you work out the order. Not every board type comes in every length.

How to work out how many sheets you need

  1. Measure every face you're boarding. A stud partition boarded both sides has two faces. A second layer of board counts as another face.

  2. Work out the area of each face: length x height. For a ceiling, length x width.

  3. Take off the doors and windows to get the net area.

  4. Add your waste allowance: 10% for a simple run, 15% with doors or windows, 20% for complex angles, curves or reveals. Use the higher figure for fire-rated or acoustic board. Our plasterboard waste percentage page explains how to choose.

  5. Divide by the area of one sheet and round up. Never round down.

Worked example: stud wall with a door

A stud partition 4.8m long and 2.7m high, one layer of board each side, with one door opening 0.9m wide and 2.1m high.

Sheets are 2700 x 1200mm, so 3.24m² each.

  • One face: 4.8 x 2.7 = 12.96m²

  • Less the door: 12.96 - 1.89 = 11.07m²

  • Both faces: 11.07 x 2 = 22.14m²

  • Add 15% because there's an opening: 22.14 x 1.15 = 25.46m²

  • Sheets: 25.46 ÷ 3.24 = 7.86, so order 8

On the net area alone you'd order 7 and come up one short.

15% is a safe, conservative allowance for a wall with openings. It's a guide, so adjust it to suit the job and the way you work.

Quick check by counting along the wall

When the sheet length matches the wall height, you can check the answer by counting sheets along the wall. A 1200mm sheet covers 1.2m of wall, so a 4.8m wall takes 4 sheets per face, or 8 for both sides. The door offcut is rarely big enough to use elsewhere, so the count matches the area method.

Use the figures as a starting point. Check them against your board layout and the specification before you order.

Ordering more than plasterboard?

Sheets are one line on a drylining order. Our free Drylining Waste Guide gives waste allowances for metal stud, track, insulation, screws and fixings, jointing compound and tape, plus five rules for ordering.

Common questions

How many m² is a sheet of plasterboard?

A 2400 x 1200mm sheet is 2.88m². A 3600 x 1200mm sheet is 4.32m². Multiply the length by the width in metres for any other size.

How many sheets of plasterboard do I need for a ceiling?

Use the same method. Multiply the length of the room by the width, add your waste allowance and divide by the area of one sheet. For a simple rectangular ceiling, a standard 10% waste allowance is usually enough.

How many sheets of plasterboard for a stud wall?

Work out the area of both faces, take off the openings, add waste and divide by the sheet area. The worked example above shows a 4.8m wall with a door needing 8 sheets of 2700 x 1200mm board.

Should I round up or down?

Always round up to the next whole sheet. Running short partway through a job usually costs more than a spare sheet.

Is there a plasterboard calculator?

The method above is the calculation: area of every face, less openings, plus waste, divided by the sheet area. We're building QFitout, drylining quoting software that does this for you from your measurements, along with the studs, track, fixings and the rest of the job. Join the waitlist to hear when early access opens.

We're building QFitout, drylining quoting software that applies these allowances for you when you price a job.

Join the waitlist to hear first when early access opens.

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