What Is Nominal Size vs Actual Size on a Walk-In Tub?

Nominal size and actual size are two ways of describing the same walk-in tub. The nominal size is the rounded figure used in the product name and brochure, such as Petite 28x52. The actual size is the measured dimension printed on the spec sheet, such as 27.5 x 52 x 35 inches for that same Petite. Both are correct for their purpose, but only the actual size should be used to plan an installation.

How It Works

Nominal names keep the lineup easy to talk about: a 30x52 tub, a 30x60 tub, a 36x72 tub. The spec sheet then records what the shell actually measures, often to the eighth of an inch. Whenever the two differ, the spec-sheet actual size is the figure to use. The spec sheet also carries a separate shipping size, which is the crated dimension: use it to plan the delivery path, and use the actual tub width for the doorways and hallways the tub itself must pass, since the crate can be opened outside and the tub carried in by the frame.

Imperial figures are the authoritative ones. Several spec sheets carry metric misprints, so use inches and pounds and leave the metric conversions aside.

Which Ella Models Have It

Every Ella model has both a nominal and an actual size. A few examples show how they relate. The Petite is nominally 28x52 and actually 27.5 x 52 x 35 inches. The Standard is nominally 30x52 and actually 29 5/8 x 52 3/4 x 37.5 inches. The Big4One measures 33 1/8 x 66 x 39.5 inches. And the Elite is 30 x 52 x 35 inches exactly, so its nominal and actual widths happen to match. Left-hand and right-hand versions of any model share the same measurements, mirrored. The full table is in Walk-in tub dimensions by model.

What to Know as an Owner

Frame your alcove, fit your tile flange and plan your extension panel from the actual size, never from the name. If an older manual or brochure shows a figure that disagrees with the current spec sheet, the spec sheet wins; one older manual table, for example, lists a Petite width that does not match the spec sheet, and that entry is a misprint. Keep the current spec sheet for your model with your paperwork, then read How to read an Ella spec sheet so every line makes sense.

For delivery, measure the route against the shipping size using Will it fit through my doorway?. When you contact the team about fit, have the model name, the actual size from the spec sheet, and your own measurements of the opening or doorway ready; that removes the guesswork on both sides.

Related Guides

• Will a 60 Inch Tub Fit a 60 Inch Alcove? Stud Walls, Finished Walls and Doorway Clearance
• What Is the Ella Petite Walk-In Tub and Who Does It Fit?
• Can a 32 Inch Walk-In Tub Fit Through a 32 Inch Doorway?
• Will a Walk-In Tub Fit Through a Standard Bathroom Doorway?
• Are there walk-in bathtubs only 28 inches wide for small bathrooms?
• How big is a standard bathtub, and how do you measure yours?

Common Questions