Reference

Standard shelf dimensions: a practical reference

The short version: for most home shelving, aim for 25–30 cm depth, 20–30 cm of vertical space between shelves, and keep each shelf under about 70 cm wide in 18 mm MDF before adding a center support. Heavier loads and longer spans need thicker shelves or a stronger material. Here are the details.

Shelf depth (front to back)

Depth depends on what you store.

Use	Typical depth
Paperbacks, small items	18–22 cm
General books, most shelving	25–30 cm
Binders, large books, display	30–40 cm

A depth of 28–30 cm suits most general-purpose shelving.

Vertical spacing (gap between shelves)

Leave a little headroom above the tallest item.

Contents	Spacing
Paperbacks	~20 cm
Hardbacks, larger books	~28–30 cm
Display, decor, baskets	35 cm and up

Shelf span (width between supports)

This is where most shelves fail: too wide, and the shelf sags over time. For 18 mm MDF, a common DIY material:

Shelf width	Light load	Medium load	Heavy load
Up to 70 cm	OK	OK	Add a center support
71–110 cm	OK (watch heavier use)	Add a center support	Add a support; consider plywood or 25 mm
Over 110 cm	Add a center support	Add a support; consider plywood or 25 mm	Not safe in 18 mm: use plywood or 25 mm shelves

In short: keep an unsupported 18 mm MDF shelf under about 70 cm for everyday loads. Wider shelves need a center divider, thicker boards, or a stronger material like plywood.

Shelf thickness

12 mm: light loads, short spans only.
18 mm: the standard for most home shelving.
25 mm or plywood: long spans or heavy loads (books, records, tools).

Height and safety

Tall units tip over, especially with children around. Anchor any unit 120 cm or taller, or in a child's room, to a wall stud with anti-tip hardware. This is not optional for tall or child-facing furniture.

How Kamba uses these rules

Kamba applies these limits to your exact dimensions automatically. When you enter a width, depth, material, and expected load, it checks the span against the safe limits above, adds a center support when needed, flags when a stronger material is required, and includes the right anti-tip hardware. You get a plan that is validated to hold, not a guess.