Plywood Calculator - How Many Sheets You Need (UK)
Pop in the area you need to cover and we'll work out how many sheets of ply or OSB to order, with a bit spare for cuts.
Interested? Then → Quotato for Flooring Fitters · More advice on the Blog & Chips guides.
How to use this calculator
Enter the total area you need to sheet over and choose plywood or OSB. We'll tell you how many full 2440×1220mm sheets to buy, including a sensible 10% allowance for cuts.
How we calculate this
- A standard UK 2440×1220mm sheet covers 2.977 m² (2.44 × 1.22).
- Sheets needed = area ÷ 2.977.
- We add 10% wastage for cuts and offcuts, then round up to whole sheets.
Worked example
Boarding a 20 m² loft floor: 20 ÷ 2.977 = 6.72 sheets bare. Add 10% and round up and you'll want 8 sheets of 18mm ply or OSB.
UK notes & gotchas
- Standard UK board size is 2440×1220mm (8ft × 4ft) - most merchants stock this.
- 18mm is the usual thickness for flooring; 12mm or 9mm is common for walls and roofing.
- OSB3 is the moisture-resistant grade and is usually cheaper than ply for the same job.
FAQ
What size is a standard sheet of plywood?
In the UK it's 2440×1220mm (roughly 8ft × 4ft), about 2.977 m² per sheet.
Why add 10% wastage?
Cuts around edges, doorways and pipes leave offcuts you can't always reuse - 10% stops you running short.
Should I use ply or OSB?
Both work for most flooring and sheathing. OSB3 is moisture-resistant and cheaper; ply is a touch stronger and neater on show faces.