How to size a shower
Measure the cutout, not the existing unit
Minimum code-compliant shower stall in most US jurisdictions is 30″×30″; 32″×32″ is comfortable; 36″×36″ is generous. ADA-compliant transfer showers are 36″×36″; roll-in showers are 30″×60″. Door swing or curtain track determines the actual usable space — a hinged glass door eats 24″ of swing room outside the stall.
Plumbing and electrical reduce usable depth
Supply lines, drains, vent ducts, and electrical run in the back 3–4″ of most cabinets. The catalog dimension assumes those connections sit flush against the back wall. If a previous installation routed lines along the side, the new unit may not fit even though the cutout looks correct. Pull the existing unit before ordering to confirm.
Standard vs. compact sizing
Square stalls: 32″, 36″, 42″, 48″. Rectangular / corner: 36″×48″, 36″×60″. Walk-in: 60″×36″ with no door, requires careful slope to drain.
Common mistakes
- Assuming all "standard" units in the same category are interchangeable. Cabinet height varies by 1–2″ between brands.
- Adding new flooring under the existing unit; the new layer traps the unit under the counter.
- Ignoring door swing or pull-out clearance in front of the unit.
- Mixing US and EU standards. EU appliances are sized in centimetres (60 cm ≈ 23.6″), not 24″.