Plywood is sold in many thicknesses, commonly between about 4 mm and 25 mm, with exact sizes depending on the brand. The right one depends on span, load and how the part is fixed.
Common practice by part
| Part | Thickness often used |
|---|---|
| Back panels, drawer bottoms | 4 to 8 mm |
| Wall panelling, light partitions | 6 to 12 mm |
| Short shelves | 12 mm |
| Carcass sides, tops, bottoms | 18 mm |
| Long shelves | 18 mm with support |
| Shutters | 16 to 19 mm, depending on hardware |
| Tabletops, bed platforms | 18 to 25 mm |
These are not rules. Your designer or carpenter will decide for your design.
Nominal vs actual
An "18 mm" sheet may measure slightly different from 18 mm. Check with a calliper and ask your carpenter what tolerance their joinery needs. Hinges, channels and cam fittings expect a certain thickness.
When to go thicker
- Long unsupported spans
- Heavy loads, such as bed platforms
- Screws going into an edge
When thinner is fine
- Hidden back panels
- Short spans
- Items laminated on both sides for stiffness
Ask for prices by thickness in your enquiry so that we can quote each line. See our plywood page.