How to size a bathroom vanity
Measure the cutout, not the existing unit
Bathroom vanity widths come in 24, 30, 36, 48, 60, 72″. Depth is typically 21″; standard height is 32″, comfort height is 36″ (matches kitchen counter height). Sink cutouts are pre-made on prefab vanity tops; custom tops follow the vanity's drawer/door layout.
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
Single-sink: 24–48″. Double-sink: 60″ minimum, 72″ comfortable. Each sink needs 30″ of countertop centred on it. Allow 21″ of clear floor in front for door swing.
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″.