Plasterboard Calculator UK
Work out how many plasterboard sheets you need for one wall or ceiling. Use measured dimensions or a known area, deduct major openings, enter the actual board size and choose your own cutting allowance.
Calculate plasterboard sheets
Enter a known surface area, or leave it blank and use length × height/width. If a known area is entered, it takes priority over the dimensions below.
How many plasterboard sheets do I need?
Start with the surface you are actually boarding. For one rectangular wall or ceiling, multiply its two dimensions. Deduct any large openings you genuinely will not cover, then divide the net area by the face area of one plasterboard sheet. The calculator keeps the theoretical count, your chosen extra allowance and the final whole-sheet purchase quantity separate.
Worked example: a 5 m × 2.4 m wall
UK plasterboard sheet sizes: use the board you are buying
A 2400 × 1200 mm sheet is widely available and covers 2.88 m², but it is not the only UK format. Current British Gypsum and Knauf ranges also include boards such as 1800 × 900 mm, 2500 × 1200 mm, 2700 × 1200 mm and 3000 × 1200 mm, depending on product. That is why the length and width fields stay editable.
2400 × 1200 mm
Face area: 2.88 m². A common full-size format across UK manufacturer ranges.
1800 × 900 mm
Face area: 1.62 m². Smaller formats exist for some board ranges.
Longer 1200 mm boards
2500, 2700 and 3000 mm lengths are also listed for selected products. Check the exact product before ordering.
Should you deduct windows and doors?
Deducting a large opening gives a more accurate net surface area, but square metres do not understand the cutting layout. A small opening in the middle of a sheet may save little or no full-board quantity. Treat the deduction as geometry and the cutting allowance as a separate judgement.
Why the calculator starts with 0% extra
There is no honest universal plasterboard waste percentage. A long straight wall with a board format that matches the height can behave very differently from a room with reveals, chimney breasts, short returns and many cuts. Start from the mathematical sheet requirement, then enter an allowance that reflects the real layout and your likely reuse of offcuts.
Walls and ceilings: calculate separately when the job differs
The sheet-count maths is the same, but walls and ceilings can use different board products, sizes, orientations or specifications. Run each different surface or board type separately rather than combining unlike materials into one number.
What this calculator does — and does not do
It calculates sheets
Surface area, openings, board face area, theoretical sheet count, your allowance and whole sheets to buy.
It does not design the layout
It does not optimise staggered joints, framing positions or cut reuse. A drawing-based take-off can differ from a pure area estimate.
It does not choose the board
Board type, thickness and system suitability depend on the project specification and manufacturer guidance.
Planning estimate only. Verify dimensions, board type, thickness, fixing method and system requirements against current drawings and the manufacturer information for the exact plasterboard you intend to use.
Useful next steps
- Need board dimensions? Use the UK Plasterboard Sheet Sizes reference.
- Need the manual method? Read How to Work Out How Many Plasterboard Sheets You Need.
- Already know the board count? Estimate fixings with the Plasterboard Screw Calculator.
- Planning framing as well? Use the Stud Wall Materials Calculator.
- Planning a whole room? Use the Plasterboard Room Estimator.
Frequently asked questions
How many plasterboard sheets do I need?
Divide the net area you need to cover by the face area of the sheet you are buying, add any cutting allowance you choose, then round up to whole sheets. This calculator shows those steps separately.
What size is a standard plasterboard sheet in the UK?
There is no single universal size. 2400 × 1200 mm is widely available, but British Gypsum and Knauf both list other board lengths and widths. Use the exact dimensions of the product you intend to buy.
Should I deduct doors and windows?
Large openings can be deducted from the measured surface. For small openings, remember that the cut-out does not necessarily reduce the number of full sheets you must purchase.
How much extra plasterboard should I allow for cuts?
That depends on the layout, board orientation, number of corners and openings, damage risk and whether offcuts can be reused. The calculator deliberately starts at 0% so the choice stays visible.