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Drywall / Plasterboard Calculator

Estimate sheets and supporting materials for walls and ceilings.

My ProjectNo saved space selectedSave a room once and reuse it here.

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Calculator inputs

Drywall / plasterboard project

Ready to calculate

Area to cover

Use a saved room or enter dimensions manually. Choose whether you are boarding the four walls, the ceiling, or both.

Project typeRoom lengthRoom widthWall heightProject units

Doors & windows

Openings are deducted from wall area. Adjust the average areas if your openings are unusually large or small.

DoorsWindowsAverage door area (m²)Average window area (m²)

Board & allowance

Enter the actual sheet size you plan to buy. The calculator rounds up to whole sheets.

Sheet length (m)Sheet width (m)Waste allowance

Planning screws per sheet

Optional cost estimate

Add the sheet price to estimate the main board purchase cost. Tape, compound, screws and delivery are not included.

CurrencyPrice per sheet

Material estimate only. Framing layout, board orientation and local installation rules can change actual usage.

Your estimate

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Ready when you are

Estimate sheets, waste and helpful finishing-material allowances from your room dimensions.

Plan with confidence

How to use the Drywall / Plasterboard Calculator

Estimate drywall or plasterboard sheets for a whole room, a single wall or a ceiling, with optional deductions for doors and windows.

Step by step

What to enter

Choose whether you are covering a room, a single wall or a ceiling.
Enter dimensions or load a saved room from My Project.
Enter the sheet size you plan to buy and select a waste allowance.
Optionally estimate screws per sheet and enter a sheet price.

Method

How the calculation works

PlanCalq calculates the relevant wall or ceiling surface area, subtracts selected openings, adds the chosen waste allowance and divides by the face area of one sheet.

The sheet count is rounded up because partial sheets still require purchasing a complete board. Supporting screw quantities are shown as a rough planning allowance based on the screws-per-sheet input.

Calculation summaryNet surface area × (1 + waste %) = recommended board coverageRecommended coverage ÷ sheet area = sheets required (rounded up)Sheets × screws per sheet = rough screw quantity

Worked example

Example: drywall for the four walls of a small room

Room: 4 m × 5 m × 2.7 m
Openings: 4 m²
Sheet: 1.2 m × 2.4 m
Waste: 10%

Planning resultThe walls provide about 44.6 m² of net coverage; after waste, about 49.1 m² is planned, or roughly 18 standard 1.2 m × 2.4 m sheets.

The room perimeter is 18 m, which gives 48.6 m² of gross wall area at 2.7 m high. After openings and waste, the calculator converts coverage into whole sheets rather than leaving a fractional board quantity.

Interpret the output

How to read the result

Use sheet count as a purchasing estimate, then review the room layout to decide whether different board sizes reduce joints or waste.
Tape, compound and screw estimates are supporting allowances and should be checked against the finishing system you plan to use.
If you include a ceiling, its board orientation and framing spacing may affect the practical sheet plan.

Planning limits

What this calculator does not cover

The calculator does not design framing, fire-rated assemblies, moisture-resistant assemblies or structural bracing.
Openings, niches, bulkheads and complex ceilings can change board cutting efficiency.
Local code and manufacturer requirements determine board type, thickness and fastening details.

PlanCalq methodology & safety boundaries →

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Common questions