Plaster Board Calculator

Plasterboard, also called drywall or gypsum board, is the standard way to line walls and ceilings in UK homes. Whether you're boarding a loft, building a stud wall or renovating a room, ordering the right number of sheets saves money, trips to the merchant and waste.

Our Plaster Board Calculator works out how many sheets you need, plus approximate screws, joint tape and jointing compound. This guide explains how to measure, which boards to choose and how to avoid common mistakes.

Standard plasterboard sizes in the UK

Plasterboard is sold in a few standard sizes. The most common is 2,400 × 1,200mm, which covers 2.88m². Others include:

Smaller boards are easier to carry and fit through doors and loft hatches, but mean more joints to tape and fill.

How to use the calculator (Plaster Board Calculator)

1. Choose whether you're boarding walls or a ceiling.
2. For walls, enter the total length of all the walls and the height. For a ceiling, enter its length and width.
3. Enter the area of doors and windows to subtract.
4. Pick your board size and a waste allowance, typically 10%.
5. Optionally, add a price per board to estimate the cost.

The calculator shows the number of sheets, plus approximate screws, joint tape and jointing compound.

A worked example

A room with 14m of walls at 2.4m high has 33.6m² of wall. Taking off 3.5m² for a door and window leaves 30.1m². Using 2,400 × 1,200mm boards with a 10% allowance, you'd need 12 sheets, around 330 screws, 40m of joint tape and about 9kg of jointing compound. At £12 a board, that's about £144 for the boards. Try your own room in the Plaster Board Calculator.

Choosing the right type of plasterboard

Not all plasterboard is the same. Common types include:

• Standard board: for most walls and ceilings.
• Moisture-resistant board (often green): for bathrooms, kitchens and utility rooms.
• Fire-resistant board (often pink or red): for garages, escape routes and where Building Regulations require fire protection.
• Acoustic board (often blue): denser board to reduce sound between rooms.
• Thermal or insulated board: plasterboard bonded to insulation, for external walls.

Thickness matters too. 12.5mm is standard for walls, while ceilings often use 12.5mm or 15mm depending on joist spacing and fire requirements.

Fixings, tape and finishing

Screws

Use drywall screws long enough to go into the timber by at least 25mm. Screws are typically spaced about 230mm apart on walls and closer, around 150mm, on ceilings. The calculator gives a wall-based estimate; allow more for ceilings.

Taping and jointing

If you're taping and jointing rather than plastering, you'll need joint tape for the seams and jointing compound to fill and feather them. Tapered-edge boards make jointing easier.

Skimming

Many UK plasterers apply a thin skim coat of finishing plaster over the whole board, which gives a smooth surface. If you're skimming, you'll use scrim tape on the joints instead of paper tape.

Tips for a good result

1. Stagger joints so they don't line up across rows.
2. Fix boards with the paper side out, and the long edges across ceiling joists.
3. Leave a small gap at the floor to avoid moisture wicking up.
4. Use a board lifter for ceilings. Plasterboard is heavy, and holding it overhead is hard and risky.
5. Order a few spare boards, as corners get damaged in transport.

Plasterboard vs suspended ceilings

For offices or basements where you need easy access to services, a suspended ceiling may be better. Our false ceiling calculator works out the tiles and grid for that option.

Measuring walls and ceilings

Measure each wall's width at floor level and its height from floor to ceiling, then add the widths together for the total length. For rooms with sloping ceilings, such as lofts, split the area into rectangles and triangles and work out each one. Measure door and window openings separately so you can subtract them. When in doubt, round up: it's better to have one spare board than to run short halfway through a job.

Storing plasterboard

Store boards flat, off the ground and indoors, as damp boards can warp and break. Stacking boards against a wall for long periods can bend them.