How do I measure my bathtub and alcove for a replacement?

To measure your bathtub for a replacement, take three figures from the opening the tub sits in: the length along the back wall, the width from the back wall to the front edge of the tub, and the height from the floor to the rim, then note which end the drain is on. Compare those figures with the actual size printed on a replacement tub's spec sheet rather than the nominal size in its name, because a tub named 28 inches wide measures 27.5 inches and a tub named 60 inches long can measure 59 inches. How wide are walk-in tubs, and do bathtubs come 34 inches wide? lists the published widths; this page walks through the measuring itself and what to do with the numbers.

Start with the Opening, Not the Old Tub

Most bathtubs, walk-in or conventional, are built around the same three-wall alcove that a standard 60 inch bathtub occupies, so the opening is the thing every replacement is measured against. In Ella's published size comparison the standard bathtub appears as the reference row: a 60 inch alcove with a soaking depth of about 11 inches and no overall height listed, because a standard tub is described by the depth of its water rather than by its wall. A tub has to fit your bathroom in all three directions, so take all three.

1. Length. Measure wall to wall along the back of the alcove. A 60 inch opening is the common case. The 60 inch models fill it outright, and Ella's 52 and 55 inch models use an extension panel to fill the leftover gap at one end. A tub longer than the opening, such as the LayDown72 with an overall length of 71 3/4 inches on its drawing, needs a longer run of wall than a straight replacement.
2. Width. Measure from the back wall to the outer front edge of the existing tub. Published Ella walk-in widths run from 27.5 inches on the Petite to 32 inches on the LayDown72 and the two-seat tubs, and the conventional Solo and Fiji measure 32 and 36 inches. The width of the alcove has to be measured as carefully as the length, because a few inches of width is what separates one model from the next.
3. Height. Measure from the floor to the top of the rim. Walk-in tubs stand from 21 inches on the LayDown 30x60 to 35 inches on the Petite and Elite and 40 inches on the Lounger and Transfer60, and the height sets where the deck and the seat land, and what the faucet wall and any shower curtain have to clear.
4. Drain and door side. Standard house plumbing for a bathtub is an inch and a half drain, as an installer notes in one of Ella's videos. On an Ella walk-in tub the door and the drains are on opposite sides: a right-side door tub has its drains on the left, and a left-side door tub has its drains on the right, as you face the tub. Note which end your drain is on, because that decides which door side a walk-in replacement needs.

Measure the Soaking Depth of the Tub You Have

The second set of figures compares the water, not the footprint. On every Ella tub the published depth is measured to the overflow, because water rises to the overflow opening and then runs out; measuring to the rim produces a figure you can never fill to. A tub with no seat, which includes your current standard bathtub, is measured from the floor of the tub to the center of the overflow. A standard tub soaks about 11 inches that way, while the LayDown 30x60 reaches 15 3/4 inches.

A seated walk-in tub is measured differently, and both videos on this page show the three factors: a measurement from the top of the seat to the center of the overflow, the length of the seat, and the interior length of the tub. Hold the tape flat on the seat and run it straight up to the center of the overflow for the seat-to-overflow depth. Measure the seat from its front edge to the backrest, since a shorter seat lets you settle lower and a longer seat holds you more upright. Measure the interior length end to end inside the shell for legroom, and measure the seat width, which must be wider than your seated hips. How do I measure the soaking depth of a bathtub? covers those steps in detail.

Nominal Size Versus Actual Size

The size in a tub's name is the nominal size, the rounded figure used in the model name and on the brochure. The actual size is the figure on the spec sheet drawing, and it is the one to measure your alcove against. The gap between the two is small but real:

• The Petite is 28 by 52 nominal and 27.5 by 52 by 35 inches actual.
• The Lounger is 27 by 60 nominal and 27 by 59 by 40 inches actual.
• The Transfer60 is 30 by 60 nominal and 29.5 by 60 by 40 inches actual.
• The HomeCare transfer bathtub is 32 by 60 nominal and 31 1/2 by 59 7/8 inches on the drawing.
• The LayDown72 is 72 inches long nominal and 71 3/4 inches overall on the drawing.

Ella sizes are written width by length by height, so a 30 by 52 by 35 tub is 30 inches wide, 52 inches long and 35 inches high. Write your own three figures in the same order and the comparison is direct. Four of the 60 inch models are also offered without jets, with the same footprint as the jetted version; Which 60 inch Ella walk-in tubs come without jets, and how big are they? sets their nominal and actual sizes side by side.

Replacement Sizes Side by Side

Here is what the table means for your bathroom. If your alcove is 60 inches long, the Solo, the LayDown 30x60 and the Lounger fill it outright, and the 52 inch Elite and Petite fill it with the extension panel. If you want more water than the roughly 11 inches a standard tub holds, every tub in the table that lists a depth soaks deeper, from 15 inches on the LayDown sizes to 17 inches on the Solo. If the bather is over six feet tall or wants a full-length reclined soak, the LayDown72 needs a foot more wall than the standard alcove, which is what What is an oversized bathtub and who actually needs one? means by oversized, so measure the run of wall before you commit to the length. And the heights show that moving from a standard tub to a seated walk-in raises the rim to 35 or 40 inches, so plan the window, the faucet wall and the shower curtain or door around the new height. Your Ella dealer or the team at (800) 480-6850 can send the spec sheet for any model not in the table.

Watch: How to Measure the Soaking Depth in Your Walk-In-Tub | Ellas Bubbles with chapters and a full transcript.

Related Guides

• Will it fit my alcove? Extension panels, end panels, and 60 inch spaces
• How many gallons of water does a walk-in tub hold?
• What Size Water Heater Do I Need for My Walk-in Tub?

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