A1 · Woodworking calculator
Plywood & Sheet Material Calculator
Work out how many sheets of plywood, MDF or OSB you need for one rectangular surface. Compare both sheet orientations, add your own allowance and estimate handling weight from the density you enter.
Free to use · no account needed · calculations stay in this browser · formula reviewed 4 September 2026
When to use this sheet calculator
If the question is simply how many sheets of plywood, MDF or OSB you need to cover a floor, wall, roof or run of cabinet backs, this is the calculator to use. It checks both rectangular sheet orientations and then applies the allowance you enter. If you already have a list of exact parts, use the cut list optimiser instead.
The worked example uses a 2440 × 1220 mm sheet. Enter the dimensions your supplier actually quotes rather than assuming every product uses that size.
Density varies by product, grade, moisture and manufacturer. The weight line uses only the density you enter; check the supplier specification before using it for lifting or transport.
Worked example
A 3000 × 2400 mm surface covered with 2440 × 1220 mm sheets needs a three-sheet rotated grid before allowance. Adding 10% rounds the purchasing plan to four sheets. At the entered example density of 600 kg/m³ and 18 mm thickness, those four full sheets weigh about 128.6 kg in total.
Blank bench check
| Surface | _____ × _____ mm |
|---|---|
| Sheet | _____ × _____ × _____ mm |
| Face/grain direction | ____________________ |
| Defects and trim | ____________________ |