What you need
- A 25-foot tape measure (a cloth sewing tape is fine for the body measurements)
- Your phone, for photos
- A pencil and the checklist below, or just a notes app
- A helper, if possible. Long measurements are easier with two people.
Measure in inches, and round down rather than up. A tub that is a half inch too big does not fit.
Step 1: the alcove or footprint
Most walk-in tubs go where an existing tub sits, in a three-wall alcove. Measure:
- Length, wall to wall. Measure along the back wall at the top of the existing tub and again near the floor. Walls are rarely perfectly square, so use the smaller number. Many standard alcoves are close to 60 inches, but check yours.
- Depth, front to back. From the back wall to the outside edge of the current tub. Standard tubs are often around 30 to 32 inches deep; many walk-in tubs are similar, and some are wider.
- Height available. Note anything that hangs low: a window sill on the back wall, a soap niche, a shower valve. Walk-in tubs are taller than standard tubs, so a window that cleared the old tub may not clear the new one.
Take a straight-on photo of the whole tub area and a close-up of the faucet and drain end.
Step 2: which end is the drain?
Stand facing the tub. Is the faucet and drain on your left or your right? Walk-in tubs are ordered as left-hand or right-hand drain models, and matching the existing drain usually keeps plumbing simpler and less expensive. Write it down: drain on left or drain on right.
Step 3: the delivery path
This is the step people skip, and it is the one that most often changes the plan. A walk-in tub has to travel from the curb to the bathroom in one piece.
- Width of the front door opening (or whichever door the crew will use), measured inside the frame with the door open
- Width of every interior doorway on the way, especially the bathroom door itself
- Hallway width at its narrowest point, and any tight turns
- For stairs: width, and the clearance at landings and at the top where the route turns
- Any railings, radiators, built-ins or light fixtures that narrow the path
Split-level and tri-level homes, which are common in many Denver-metro suburbs, often have short flights of stairs with a turn. Photograph those turns. If a doorway is the limiting factor, sometimes removing the door from its hinges, or the door stop molding, gains enough room. Your installer can tell you.
Step 4: door swing and floor space
Walk-in tub doors open either inward, into the tub, or outward, into the room.
Inward-opening door
Needs no clear floor in front of the tub. Good for small bathrooms. The bather steps around the door as it swings in.
Outward-opening door
Leaves the tub entry fully open, which helps walker users and caregivers. Needs clear floor space in front of the tub for the door to swing.
Measure from the front of the current tub to the nearest obstacle: the toilet, vanity or opposite wall. If you are considering an outward door, that clear floor area has to be bigger than the door's swing. Note where the toilet sits; a toilet right next to the tub entry can block an outward door.
Step 5: measure the bather
A tub that fits the room but not the person is a bad purchase. Two measurements help most:
- Comfortable step height. Have the bather step up onto something of a known height, holding a counter for balance, and note what feels easy. Walk-in tub thresholds are typically a few inches high, but they vary by model.
- Seated hip width and knee height. Sitting on a firm chair, measure across the hips and from floor to the back of the knee. Compare with the tub's seat width and seat height on its spec sheet.
If the bather is tall, check interior length so knees are not jammed against the door. If the bather is a larger person, look at bariatric or wide models with wider seats and doors.
Step 6: hot water and power
- Find your water heater's label: tank size in gallons, and whether it is gas or electric. Tankless units list a flow rate instead.
- Find the tub's capacity on its spec sheet. If the tub holds close to or more than your tank's usable hot water, plan for an inline heater, a larger tank or a tankless unit.
- Note where your electrical panel is and roughly how far it is from the bathroom. Jetted and heated tubs need power, usually on a dedicated GFCI-protected circuit.
Your fit-check summary
| Measurement | Write it here |
|---|---|
| Alcove length (smallest) | ______ in |
| Alcove depth | ______ in |
| Drain end | Left / Right |
| Narrowest doorway on the route | ______ in |
| Narrowest hallway or stair point | ______ in |
| Clear floor in front of tub | ______ in |
| Bather's comfortable step height | ______ in |
| Bather's seated hip width | ______ in |
| Water heater size and type | ______ gal, gas / electric / tankless |
| Floor the bathroom is on | Main / Upper / Lower |
Send these numbers and a few photos with your quote request, or read them to us on the phone at 1-888-779-2284. With them, we can usually narrow the choice to a short list of models that genuinely fit.
Measuring questions
My alcove is not 60 inches. Can I still get a walk-in tub?
Often, yes. Walk-in tubs come in several lengths, and shorter or longer alcoves can sometimes be adjusted with wall work. Send the measurement and a photo and we will tell you what fits.
What if the tub will not fit through my bathroom door?
Removing the door and stop molding sometimes gains enough width. If not, a different model, a walk-in shower, or a doorway change may be options. This is exactly why we check the route before ordering.
Do I need to measure if someone is coming out to look?
It is not required, but having rough numbers lets us discuss realistic options on the first call, which saves you time.
Last reviewed 2026-10-10.