How to Calculate a Cabinet
From overall size to every panel: the simple breakdown of a cabinet carcase.
The carcase
A cabinet is two sides, a top, a bottom, a back and shelves. Each panel is sized from the overall dimensions minus the thickness of adjoining panels.
Standard dimensions
For a cabinet W wide, H high, D deep, with panel thickness T:
Sides: 2 × (H × D)
Top & bottom: 2 × ((W − 2T) × D)
Back: 1 × ((W − 2T) × (H − 2T))
Shelves: n × ((W − 2T) × D)
Doors and drawers
Doors: (W / n) − gap wide × full height. Drawers need slides with their own clearances — see the drawer guide.
Practical tips
- 18 mm is the standard carcase thickness.
- Leave 2–3 mm gaps between doors.
- Plan shelf heights around what you will store.
Generate the panel list instantly with the furniture plan generator.
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