Plasterboard Calculator: Sheets, Screws and Compound

Estimate only. Check product labels and the building rules in your state or territory before you buy or build.

Quick answer

Add the wall area (room perimeter × wall height) and the ceiling area, take off doors and windows, add a waste allowance and divide by the area of one sheet: a 1200 × 2400 mm sheet covers 2.88 m². A 4 × 3.5 m room with 2.4 m ceilings, one door and one window has 46.76 m² to line, which with 10% waste is 19 sheets of plasterboard, 13 for the walls and 6 for the ceiling.

How to use the plasterboard calculator

Choose Room size to type the length, width and wall height of a room in metres, or Areas to type wall and ceiling areas you measured yourself.
Pick what you are lining: walls and ceiling, walls only or ceiling only, and enter how many doors and windows the walls have.
Choose the sheet size you plan to buy. The number of sheets, the area to line, the screws and the jointing compound update as you type.
Open Waste, door and window sizes to change the 10% waste allowance or the size of your openings. Open Screws, tape and compound rates to match your framing centres and the figures on your own products.

How do you work out how much plasterboard you need?

Work out the area to line, add a waste allowance, and divide by the area of one sheet. The wall area of a rectangular room is its perimeter times the wall height; the ceiling is length times width. Doors and windows come off the wall area because no sheet goes there.

Walls and ceiling are rounded up to whole sheets separately, because offcuts from wall sheets rarely fit the ceiling. Screws and jointing compound are worked out from the area you line, before waste, using the quantities per 100 m² that CSR Gyprock publishes: 620 screws with stud adhesive on 600 mm wall framing, 750 screws on 450 mm ceiling joists, and 24 kg plus 8 kg of all-purpose compound.

wall area = 2 × (length + width) × wall height − doors − windowsceiling area = length × widthsheets = area × (1 + waste %) ÷ area of one sheet, rounded upscrews = wall area × 6.2 + ceiling area × 7.5 (adhesive and screws, 600 mm wall framing, 450 mm ceiling joists)jointing compound (kg) = area × 0.32

What size plasterboard sheets can you buy?

Standard 10 mm plasterboard comes 1200 mm wide in lengths from 2400 to 6000 mm, and also 1350 mm wide, according to CSR Gyprock, which notes that stock of particular sizes varies by region. The calculator lists both widths in every length, but the page does not say which combinations are stocked, so check with your supplier. The weights below are worked out from its nominal 5.7 kg per m² for 10 mm board.

10 mm plasterboard sheets 1200 mm wide: area per sheet, sheets per 10 m² before waste and approximate weight
Sheet	Area per sheet	Sheets per 10 m²	Weight at 5.7 kg/m²
1200 × 2400 mm	2.88 m²	3.47	16.4 kg
1200 × 2700 mm	3.24 m²	3.09	18.5 kg
1200 × 3000 mm	3.60 m²	2.78	20.5 kg
1200 × 3600 mm	4.32 m²	2.31	24.6 kg
1200 × 4200 mm	5.04 m²	1.98	28.7 kg
1200 × 4800 mm	5.76 m²	1.74	32.8 kg
1200 × 5400 mm	6.48 m²	1.54	36.9 kg
1200 × 6000 mm	7.20 m²	1.39	41.0 kg

CSR Gyprock recommends full-length sheets where possible, to keep butt joints at sheet ends to a minimum.

Worked examples

Walls and ceiling of a 4 × 3.5 m bedroom

The room is 4 × 3.5 m with 2.4 m ceilings, one 90 × 200 cm door and one 120 × 120 cm window. The walls are 2 × (4 + 3.5) × 2.4 = 36 m². The door takes off 1.8 m² and the window 1.44 m², leaving 32.76 m². The ceiling is 14 m², so the area to line is 46.76 m².

With 10% waste, the walls need 32.76 × 1.1 ÷ 2.88 = 12.51, so 13 sheets of 1200 × 2400 mm, and the ceiling 14 × 1.1 ÷ 2.88 = 5.35, so 6 sheets: 19 in all. With stud adhesive, 6.2 screws per m² on the walls and 7.5 on the ceiling make 309 screws, about 19 per sheet, and at 0.32 kg per m² the job takes 14.96 kg of all-purpose jointing compound, one 20 kg bucket.

A 6 × 4.8 m open-plan ceiling in long sheets

Only the ceiling of a 6 × 4.8 m living area gets new plasterboard: 28.8 m², or 31.68 m² with 10% waste. In 1200 × 4800 mm sheets (5.76 m²) you need 31.68 ÷ 5.76 = 5.5, so 6 sheets; in 1200 × 6000 mm sheets (7.2 m²) you need 4.4, so 5, with fewer butt joints to set.

At the default ceiling rate of 7.5 screws per m², which is CSR Gyprock’s 750 per 100 m² with adhesive on joists at 450 mm centres, the ceiling takes 216 screws; the table below gives the rate for other framing centres. The compound comes to 9.22 kg, one 20 kg bucket.

How many screws do you need for plasterboard?

With stud adhesive and screws on framing at 600 mm centres, CSR Gyprock allows 620 screws per 100 m² of plasterboard per layer, about 18 per 1200 × 2400 mm sheet. Its guide says the generally recommended fixing for interior work is adhesive combined with screws or nails; screws alone take more.

Fixing materials per 100 m² of plasterboard, one layer, from CSR Gyprock’s Red Book 2, Table 3
Fixing and framing centres	Adhesive per 100 m²	Screws per 100 m²	Screws per 1200 × 2400 sheet
Adhesive and screws, 600 mm	3.5 kg	620	18
Adhesive and screws, 450 mm	4.2 kg	750	22
Screws only, horizontal sheets, 600 mm	none	820	24
Screws only, horizontal sheets, 450 mm	none	1,000	29
Screws only, vertical sheets, 600 mm	none	1,150	33

With adhesive and nails on 600 mm framing the guide allows 3.5 kg of adhesive and 1.0 kg of nails per 100 m². Stud adhesive is never a fixing on its own and must not be relied on in fire-rated systems.

How much jointing compound do you need?

Plan on about 0.32 kg of all-purpose premixed jointing compound per m² of plasterboard: CSR Gyprock rates its 20 kg bucket (about 14 L) at 24 kg per 100 m² for the tape and second coats and 8 kg per 100 m² for the topping coat. One bucket therefore finishes about 62.5 m².

With a separate base coat and topping, CSR Gyprock’s installation guide lists 13 to 31 kg per 100 m² for the tape and second coats and 5.7 to 10 kg per 100 m² for the finish coat, depending on the product. Those figures are for sheets fixed horizontally; allow 20% more jointing material for vertical sheeting. Type the figure for your compound into the rates and the calculator uses it.

Common questions

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

A 4 × 3.5 m room with 2.4 m ceilings, one door and one window needs 19 sheets of 1200 × 2400 mm plasterboard for the walls and ceiling, including 10% for waste: 13 for the walls and 6 for the ceiling. For any other room, add the wall and ceiling areas, take off the openings, add the waste allowance, divide by the area of one sheet and round up.

How many screws per sheet of plasterboard?

About 18 screws per 1200 × 2400 mm sheet when you use stud adhesive and screws on framing at 600 mm centres: CSR Gyprock allows 620 per 100 m². On framing at 450 mm centres it is about 22 (750 per 100 m²), the rate for 10 mm board on a ceiling, which needs joists at 450 mm centres or closer. Fixing with screws only takes 24 to 33 per sheet, depending on the framing centres and whether the sheets run horizontally or vertically.

How much plasterboard compound do I need?

About 0.32 kg of all-purpose premixed compound per m², based on CSR Gyprock’s 24 kg per 100 m² for the tape and second coats plus 8 kg for the topping coat. The walls and ceiling of a 4 × 3.5 m room (46.76 m²) take 14.96 kg, one 20 kg bucket. Allow 20% more jointing material if the sheets are fixed vertically.

What size does plasterboard come in?

Standard 10 mm plasterboard comes 1200 or 1350 mm wide and 2400, 2700, 3000, 3600, 4200, 4800, 5400 or 6000 mm long, according to CSR Gyprock, though stock of particular sizes varies by region. A 1200 × 2400 mm sheet covers 2.88 m² and weighs about 16.4 kg at the nominal 5.7 kg per m². Longer sheets mean fewer butt joints.

Can you use 10 mm plasterboard on a ceiling?

Yes, on ceiling joists at 450 mm centres or closer. CSR Gyprock’s installation guide sets 450 mm as the maximum framing centres for its standard 10 mm board on interior ceilings in wind categories N1 to N5 and C1, and 300 mm in higher categories, with insulation up to 5 kg per m². For joists at 600 mm centres it lists a 10 mm ceiling board or 13 mm board instead.

How much stud adhesive do I need for plasterboard?

About 3.5 kg per 100 m² of plasterboard on framing at 600 mm centres, and 4.2 kg at 450 mm centres, according to CSR Gyprock’s fixing table. The walls and ceiling of a 4 × 3.5 m room (46.76 m²) therefore take about 1.6 kg at 600 mm centres. Stud adhesive is always used together with screws or nails, never on its own, and is not relied on in fire-rated systems.

Sources

CSR Gyprock, Gyprock Plus (product page) (checked 19 October 2026)10 mm board, widths 1200 and 1350 mm, lengths 2400 to 6000 mm; nominal 5.7 kg/m²; stockholdings vary by region; best for ceilings with 450 mm joist centres.
CSR Gyprock, The Red Book 2: Residential Installation Guide, Class 1 & 10 Buildings (checked 19 October 2026)Table 3 fixing materials per 100 m²; Table 13 maximum ceiling framing centres; Table 23 jointing quantities per 100 m² and 20% more for vertical sheeting; adhesive used with fasteners; full-length sheets to minimise butt joints.
CSR Gyprock, All-Coat MAX (product page) (checked 19 October 2026)20 kg bucket (about 14 L); 24 kg/100 m² for the tape and second coat, 8 kg/100 m² for the topping coat.

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