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Plasterboard Quantity Calculator

Calculate sheets of plasterboard needed for a room.

What is the Plasterboard Quantity Calculator?

A plasterboard quantity calculator works out how many sheets of plasterboard you need to line a room's walls (and optionally the ceiling), based on the room's length, width and height. It works by calculating the total wall area (perimeter × height) plus the ceiling area if included, then dividing by the area of a standard 2400×1200mm sheet and adding roughly 10% for waste and cuts. To calculate it manually: wall area = 2 × (length + width) × height, add ceiling area (length × width) if needed, divide the total by 2.88m² (one standard sheet) and multiply by 1.1 for waste, then round up — this excludes door and window openings, which would reduce the real total slightly.

How it works

This works out total wall area (perimeter × height) and, if included, ceiling area (length × width), sums them, and divides by the area of a standard plasterboard sheet — with an allowance added for waste from cuts and offcuts.

UK context

Standard UK plasterboard sheets are commonly 2400mm × 1200mm (2.88m² per sheet), though other sizes are available for specific applications — always check the size of the specific product you're buying.

Tips

This calculation doesn't subtract door and window openings, so the figure is a slight overestimate for rooms with large openings — a reasonable safety margin for a typical room.
A waste allowance of around 10% is standard practice to account for cuts around corners, openings and awkward angles.
Check whether you need standard, moisture-resistant, or fire-rated board for your specific room (bathrooms and kitchens often need moisture-resistant board).

Frequently asked questions

What size is a standard plasterboard sheet?

The most common UK standard size is 2400mm × 1200mm (2.88m² per sheet), though other sizes exist for specific applications — check the exact size of your chosen product.

Does this calculator account for doors and windows?

No, it calculates the full wall area without subtracting openings, giving a slight overestimate that acts as a reasonable buffer for typical rooms with normal-sized doors and windows.