The short answer
- Measure length and width at the floor, middle and top of the tub space, and use the smallest number.
- A standard alcove tub is about 60 inches long and 30 to 32 inches wide; many walk-in tubs are made to fit it.
- Note which side the drain and faucet are on as you face the tub.
- Measure the narrowest doorway, hallway and stair turn on the way to the bathroom.
- Check the water heater size and first-hour rating, and whether an electrical circuit is available for jets.
- Photos of the tub, faucet wall, floor and water heater label help a specialist confirm the fit.
What you need
- A tape measure, ideally 25 feet.
- A pencil and paper, or your phone’s notes app.
- A phone camera.
- A helper, if possible, to hold the other end of the tape.
- About ten minutes.
You do not need to remove anything or open any walls. Everything here is measured from what you can see.
Why measuring carefully matters
A walk-in tub is a large, rigid object that has to fit three places: the tub space, the path through your home, and your household’s utilities. An inch off in any of them can turn a smooth one-day installation into a delay. Walls are rarely perfectly straight, and older homes settle, so measuring at more than one height is the single best habit you can build. When in doubt, measure twice and write down the smaller number.
Step 1: Measure the length of the tub space
Measure the alcove from wall to wall along the back of the tub. Take three measurements:
- At the floor, just above the tub rim or where the tub meets the wall.
- In the middle, about halfway up the wall.
- At the top, as high as the tub surround goes.
Write down all three and circle the smallest. That is your usable length.
A standard alcove tub is about 60 inches long. Many walk-in tubs are made to fit a 60-inch space, often with extension panels to close any small gap. Compact walk-in tubs are available down to roughly 40 to 45 inches for shorter spaces. If your space is shorter than 60 inches, see our small walk-in tubs guide.
Step 2: Measure the width
Measure from the back wall to the front edge of the tub, where the outer apron sits. Again, measure at the floor, the middle and the top, and circle the smallest number. Standard alcove tubs are usually about 30 to 32 inches wide. Many walk-in tubs range from about 26 to 33 inches wide, with two-seat models wider still.
Step 3: Measure the height
Walk-in tubs are taller than standard tubs, often 38 to 42 inches. Measure from the bathroom floor to the lowest obstruction above the tub: a window sill, a shelf, a soap niche or a grab bar. If a window sits low over the tub, it may limit your choices or need a different surround solution.
Step 4: Note the drain and faucet side
Stand in the bathroom facing the tub. Is the drain at the left end or the right end? Most walk-in tubs are made in left-hand and right-hand versions. Ordering the version that matches your drain avoids moving plumbing, which saves time and money. Also note where the faucet and shower valve are on the wall.
Step 5: Check the door swing space
Walk-in tub doors swing either inward, into the tub, or outward, into the bathroom.
- For an outward door, measure the clear floor space in front of the tub, from the tub front to the nearest obstacle, such as the toilet, vanity or opposite wall. The door needs room to open fully, and the bather needs room to stand while it opens.
- For an inward door, you do not need extra floor clearance, which is why inward doors suit tight bathrooms.
- For a wheelchair transfer tub, measure enough floor space beside the tub door for the wheelchair to park parallel to it, plus room for a caregiver if needed.
Sketch the room on paper: the tub, the toilet, the vanity and the bathroom door. Draw the door swing. You will instantly see which door style works.
Step 6: Measure the path into the bathroom
The tub has to travel from the delivery truck to the bathroom. Measure the narrowest point on that path:
- The front or side entry door.
- Any hallway, especially at corners.
- Stairways and landings, if the bathroom is upstairs or down.
- The bathroom door itself.
Measure the clear opening between door stops and trim, not the door slab. Tubs can often be tilted on their side through a doorway, so a dealer will compare your narrowest opening with the tub’s packaged depth and height. Removing a door from its hinges can gain an extra inch or more.
Step 7: Check your water heater
Find the label on your water heater and write down:
- The tank size in gallons.
- The first-hour rating, if shown on the yellow EnergyGuide label.
- Whether it is gas, electric, heat pump or tankless.
Walk-in tubs are deep, and roughly 72% of a comfortable bath comes from the heater at typical settings. Use the calculator in our water heater guide to see whether your heater can fill the tub you are considering.
Step 8: Check electrical if you want jets
Soaking walk-in tubs generally need no electrical work. Tubs with air jets, water jets, in-line heaters or heated backrests usually need a dedicated GFCI-protected circuit. Note:
- Whether there is a GFCI outlet in the bathroom.
- Where your electrical panel is, and whether it has open breaker spaces.
- Roughly how far the panel is from the bathroom.
An electrician will confirm the details, but these notes help a dealer estimate the work.
Step 9: Take four photos
Photos answer questions measurements cannot. Take:
- The tub from the bathroom doorway, showing the whole alcove.
- A close-up of the faucet wall.
- The floor in front of the tub, including the toilet and vanity.
- The water heater label.
Send these with your measurements when you request a quote.
Measure the bather, too
The right tub fits the person as well as the room. If you can, also note:
- Height, so tall bathers get enough leg room.
- Seated hip width, measured sitting in a firm chair, for seat width.
- Mobility aids, such as a cane, walker or wheelchair, and the wheelchair seat height.
- Transfer side, if the bather moves more easily toward one side.
Larger or taller bathers should see our bariatric walk-in tub guide, and wheelchair users our wheelchair-accessible walk-in tub guide.
Common walk-in tub sizes
These published examples show the range of footprints available. Always confirm the current spec sheet before ordering.
| Size category | Example models and published sizes | Fits |
|---|---|---|
| Compact | Ella’s Bubbles Front Entry, 32 x 40 in; Ella’s Mobile and Hydro Dimensions HD2645, about 26 x 45 in | Short alcoves, some shower stalls |
| Mid-size | Ella’s Capri, 30 x 52 in | Shorter-than-standard alcoves |
| Standard length | Ella’s Lounger, 27 x 60 in; Ella’s Ultimate and Transfer60, 30 x 60 in | Standard 60-inch alcoves |
| Two-seat and large | Ella’s Tub4Two and Companion, 32 x 60 in; Escape, 36 x 72 in; Big4Two, 36 x 80 in | Larger bathrooms and custom spaces |
Common measuring mistakes
- Measuring only once. Walls lean. Measure at three heights.
- Measuring the door slab instead of the opening. Measure between the stops.
- Forgetting stair landings. The tightest point is often a turn, not a door.
- Ignoring the window. A low sill can block a taller tub or surround.
- Guessing the drain side. Look, and write it down.
- Skipping the water heater. It is the most common cause of lukewarm baths.
What happens next
Once you have your numbers, a specialist can usually narrow your choices to two or three tubs in a single call. Aging Safely Baths reviews your measurements and photos, recommends models that fit both the bather and the bathroom, and sends a written, itemized quote. When you are ready, we offer one-day installation by factory-certified installers in many areas, or delivery anywhere in the US and Canada. Start with our overview of senior walk-in tubs.
Printable measuring checklist
- Length at floor / middle / top: ______ / ______ / ______ (smallest: ______)
- Width at floor / middle / top: ______ / ______ / ______ (smallest: ______)
- Height to lowest obstruction above tub: ______
- Drain side (facing tub): left / right
- Clear floor space in front of tub: ______
- Narrowest doorway, hallway or stair turn: ______
- Water heater size and first-hour rating: ______ / ______ (gas / electric / tankless)
- GFCI outlet in bathroom: yes / no; panel location: ______
- Bather height: ______; seated hip width: ______
- Mobility aids: none / cane / walker / wheelchair
- Photos taken: tub, faucet wall, floor, heater label
Measuring for a shower-stall conversion
If you only have a stall shower and want a walk-in tub, measuring is slightly different.
- Measure the inside of the stall wall to wall in both directions, at three heights.
- Measure the curb or threshold height, since it may be removed.
- Locate the drain. Stall drains are often centered; walk-in tub drains are at one end. Note the drain’s distance from each wall.
- Note the valve height and location. A tub needs a filler lower on the wall than a shower head.
- Check the ceiling height if the stall has a low ceiling or soffit.
Common stall sizes include 36 by 36, 32 by 48 and 30 by 60 inches. Compact walk-in tubs of about 26 by 45 inches can fit many 32-by-48-inch stalls, while 36-by-36-inch stalls are often too small for any tub. In that case, a curbless shower with a fold-down seat is usually the better answer. See our small walk-in tubs guide.
Measuring for a wheelchair transfer tub
Transfer tubs need two extra measurements:
- Clear floor space beside the tub door, for the wheelchair to park parallel to the tub with the door fully open.
- Wheelchair seat height from the floor, to compare with the tub’s seat height for a level transfer.
Also note which side the bather transfers toward more easily. That decides whether you need a left- or right-hand door.
How a dealer uses your numbers
Once you send your measurements, a good dealer will:
- Compare your smallest length and width with each model’s footprint.
- Match the drain side to avoid moving plumbing.
- Choose a door style that fits your clear floor space.
- Compare your narrowest doorway with the tub’s packaged dimensions.
- Compare your water heater with the tub’s fill volume.
- Check whether jets or heaters need a new circuit.
- Check seat width and interior length against the bather.
The result should be a short list of tubs that fit both the room and the person, with any extra work clearly explained. That is exactly what we do when you request a quote.
Measuring tips from installers
- Use a metal tape, not a cloth one. Cloth tapes stretch.
- Measure to the finished wall, not to tile trim or caulk beads that will be removed.
- Check for out-of-square corners by measuring the diagonal of the alcove both ways.
- Note anything in the walls you can see: access panels, vents, outlets.
- Write units clearly. Inches and fractions are easy to mix up.
Measuring for the bather: a closer look
Room measurements tell you whether a tub fits the bathroom. Body measurements tell you whether it fits the person. Seat width is the most important. Have the bather sit in a firm dining chair, measure across the widest point of the hips and thighs, and add two to three inches. Compare that with the seat width on each spec sheet. Next, measure from the chair back to the front of the knees and to the heels with feet flat on the floor. That tells you the knee room and leg room the tub needs in front of the seat. For tall bathers, compare their height with the interior length so their legs can rest under water. And for anyone with a walker, measure the walker’s width, since the space in front of an outward-swinging door must hold both the walker and the open door.
What to do if your space is borderline
Sometimes your numbers are within an inch of a tub’s footprint. Do not guess. Send the measurements and photos to the dealer, and ask whether extension panels, a different door direction or a slightly smaller model would make the fit comfortable. A tub that fits with room to spare installs faster, seals better and looks better than one forced into a space.
Send us your numbers
When your checklist is complete, call 1-888-779-2284 or request a free quote and include your photos. A specialist will match your space to tubs that fit and explain any extra work in writing, before anything is ordered.
Accurate numbers are the difference between a smooth installation day and a delay.
Frequently asked questions
What is the standard size of a walk-in tub?
There is no single standard, but many walk-in tubs are made to fit a standard alcove of about 60 inches long and 30 to 32 inches wide. Compact models go down to about 40 to 45 inches long, and two-seat models can reach 36 by 80 inches.
Will a walk-in tub fit where my current tub is?
Usually. Measure the alcove length and width at three heights, note the drain side, and compare with the tub’s spec sheet. Extension panels close small gaps.
Why measure at three heights?
Walls are rarely perfectly straight, especially in older homes. Measuring at the floor, middle and top and using the smallest number ensures the tub fits along its full height.
How do I know which side my drain is on?
Stand in the bathroom facing the tub and look at which end the drain is at. Most walk-in tubs come in left- and right-hand versions to match.
Will a walk-in tub fit through my door?
Measure the clear opening of the narrowest door or hallway on the path. Tubs can often be tilted through a doorway, so a dealer will compare your measurement with the tub’s packaged dimensions.
Do I need to measure my water heater?
Yes. Walk-in tubs are deep, and most of the bath comes from the heater. Note the tank size and first-hour rating and compare with the tub’s fill volume.
How tall is a walk-in tub?
Many walk-in tubs are about 38 to 42 inches tall. Hydro Dimensions’ HD2645, for example, is about 39.5 inches tall. Check for low windows or shelves above the tub.
Can a walk-in tub go where my shower stall is?
Often, if the stall is large enough for a compact tub. It usually requires moving the drain and adjusting supply lines, which adds work.