Measure your tub's alcove and the floor in front of it. You get the shower base that drops into the tub's place, the doors or glass that fit, the step, where the drain goes and how much tile, drawn to scale.
Your walk-in shower
60″ × 30″ shower basedrops into the tub's place · passes the code by its 25″ rule · a 1⅜–6″ step instead of the tub's 14″ · 24⅝–28¼″ way in
Doors that fit
Quick answer: a standard 60″ tub’s alcove takes a 60″ shower base, sold 30, 32, 34 or 36″ deep; one as deep as the tub drops into its place. Inside, a 60 × 30 is about 57½ × 28¾″, passing the code only by its 25″ rule; a 60 × 36 is 57½ × 31¾″. The step drops from the tub’s 14″ to 1⅜–6″, and a sliding door leaves a 24–28″ way in. Measure your alcove above and the planner draws it.
How to use the tub-to-shower conversion planner
- Measure the alcove wall to wall, along the tub, just above its rim, and say whether that is over the tile (the wall you see) or at the studs (the tile already off). A 60″ tub’s alcove usually reads 57¾ to 59″ over the tile.
- Measure the alcove’s depth: from the back wall to the front of the end walls. It is the tub’s width, most often 30 or 32″.
- Measure the clear floor in front of the tub, to the facing wall, the vanity or the toilet’s front. A deeper base and a hinged door both take some of it.
- Pick the shower floor (a base, or curbless and tiled), the end your tub’s drain is at, where the new drain goes, and the way in: a sliding door, a hinged door, a fixed glass panel or a curtain.
- Choose how high to tile and whether a window is in the shower. The answer names the base, the doors that fit your opening, the step, the drain, the tile and anything the code asks for. Copy link to this shower keeps it all.
The shower bases sold for a tub’s alcove
Inside sizes are the makers’ own figures, length by front to back. The code measures a shower inside, so this is the number that counts, not the 60 × 30 on the box.
| Base | Inside | Step in | Drain | The code’s 30″ |
|---|---|---|---|---|
| 60 × 30″ | 57½ × 28¾″ (Swanstone SBF-3060), 56½ × 25¼″ (VP6030) | 1⅜–6″ | left, centre or right | passes by its 25″ rule |
| 60 × 32″ | 57½ × 28″ (Swanstone SS-3260) | 2¼–4½″ | left, centre or right | passes by its 25″ rule |
| 60 × 34″ | 57½ × 30″ (SS-3460), 56 5⁄16 × 29⅜″ (VP6034) | 3–6″ | left, centre or right | 30″ on the SS; the VP by its 25″ rule |
| 60 × 36″ | 57½ × 31¾″ (SS-3660) | 3–3¼″ | left, centre or right | passes |
| 54 × 34″ | 51½ × 30″ (SS-3454) | 4½″ | centre | passes |
The steps are the thresholds sold at each size, from Swanstone’s barrier-free SBF-3060 (1⅜″) and American Standard’s Passage (2¼″) to the 6″ VP bases. The code: a shower at least 30″ inside at its narrowest and 900 sq in, or 25″ with at least 1,300 sq in (IRC P2708.1).
Doors for a 60″ base
| Door | Fits a finished opening of | Way in |
|---|---|---|
| MAAX Aura, Kameleon (sliding) | 55–59″ | 23½–27½″ |
| MAAX Duel (sliding) | 56–58½″ | 24½–27½″ |
| MAAX Incognito 76 (sliding) | 56–59″ | 24¼–28¼″ |
| MAAX Halo (sliding) | 56½–59″ | 22⅛–24⅝″ |
| MAAX Ibiza (sliding) | 57–59″ | about 24–26″ |
| American Standard Aspirations (sliding) | 58½–59 7⁄16″ | not printed |
| MAAX Capella 78 (hinged) | 56–59″ | 23¾–26¾″ |
| A fixed glass panel (VIGO, ANZZI) | 34″ of glass | the rest of the opening |
A door’s way in grows as its panels spread over a wider opening, so the planner reads it between the maker’s narrowest and widest. The code wants at least 22″ clear (IRC P2708.1.1), and a hinged door must open outward.
Four alcoves, planned
A 60 × 30″ tub, the alcove 59″ over the tile, 42″ of floor in front. A 60 × 30 base drops into the tub’s place: 57½ × 28¾″ inside at best, passing the code by its 25″ rule, with a 1⅜–6″ step instead of the tub’s 14″. Five MAAX sliding doors and American Standard’s Aspirations fit a 59″ opening, leaving 24⅝–28¼″ to walk through. Roomier: a 60 × 36 base with the end walls built out 6″ still leaves 36″ in front. Tile to 6 ft on the three walls: about 60 sq ft.
A 60 × 32″ tub, 60″ at the studs, 30″ in front. A 60 × 32 base drops in (57½ × 28″ inside) with a 2¼–4½″ step. The opening over it comes out at about 58⅜″, and seven sliding doors fit, about 24–27⅜″ through. A 60 × 36 would leave only 26″ in front: the code’s least, under the NKBA’s 30″.
The same 59 × 30″ alcove, curbless, with a 34″ glass panel. No base: the floor is tiled to the walls and falls ¼–½″ a foot to the drain at the old end, 1⅛–2⅛″ over 51″, so the floor is lowered to keep the entry flat. The panel leaves 25″ to walk in, over the code’s 22″.
A 60 × 28″ tub in a tight bathroom, 24″ in front. The shallowest base is 30″, so the end walls come out 2″ and leave 22″ in front: under the code’s 24″. A hinged door would need about 27″ of floor to swing out; a sliding door needs none.
Common mistakes
- Buying the base from the size on the box. A “60 × 30” base is about 57½ × 28¾″ inside, and the code measures inside. Read the maker’s drawing.
- Measuring over the old tile and buying exactly that. A 60″ base goes in against the studs, before the new backer board and tile, the way the tub did. Open one end, or measure the old tub, before you buy.
- Moving the drain without asking why. An end-drain base keeps the drain at the tub’s end, inches from where it is; a centre drain moves it about two feet under the floor.
- A hinged door in a narrow bathroom. It opens outward and needs as much floor as it is wide; a sliding door or a panel needs none.
- Forgetting the window. Glass in a shower wall with its bottom edge under 60″ above the shower floor must be safety glass (IRC R308.4.5).
- Tiling only to the shower head. The code wants a waterproof finish at least 6 ft up a shower’s walls (IRC R307.2).
Tub-to-shower conversion: questions people ask
What size shower fits where a tub was?
A standard 60″ tub’s alcove takes a 60″ shower base, 30 to 36″ deep. As deep as the tub, it drops in; deeper ones need the end walls built out into the room.
Is a 60 × 30 shower big enough?
It passes the code by its exception: about 28¾″ inside front to back, under the usual 30″, but over 1,300 sq in. The NKBA recommends 36 × 36″ inside, which no base in a tub’s alcove reaches; the deepest, 60 × 36, is 31¾″ inside.
What is the standard shower door size for a tub conversion?
Doors for a 60″ base are sold to fit a finished opening of about 55 to 59½″, each over a span; the way in is about 22 to 28″. The planner lists the ones that fit your opening; for a stall, a corner or a neo-angle shower, the shower door size finder does.
How wide should the way in be?
At least 22″ clear by the code (IRC P2708.1.1). A 34″ glass panel on a 59″ opening leaves 25″.
Do I have to move the drain?
No: bases come with the drain at either end or in the centre. An end-drain base keeps it at the tub’s end, so the plumber moves it inches.
Can a tub-to-shower conversion be curbless?
Yes, tiled with no base: the floor falls ¼–½″ a foot to the drain (IRC P2709.1), so it is lowered under the shower, or the bathroom floor raised, to keep the entry flat. The curbless shower planner sizes the linear drain and how far to drop it.
What does a tub-to-shower conversion cost?
The bathroom remodel cost calculator prices it at 2026 prices, from named sources: pick its Shower installation job.
Read next
- Luxurious walk-in shower ideas
- How cozy a small shower can be
- Shower tile combinations
- Bathroom remodel ideas without a big budget
- Small bathroom makeovers
Planning the whole room? Draw your bathroom in the free 2D planner: walls, the shower, the vanity and the toilet to scale. Building new instead? The bathtub and shower size finder sizes a tub or shower for any space, and the tile calculator counts the boxes.
About these sizes: the bases are Swanstone’s and American Standard’s, the doors MAAX’s and American Standard’s, the panels VIGO’s and ANZZI’s, read from their own pages in October 2026, and the rules the 2021 International Residential Code’s. Makers change their lines and your town may amend the code: check the base’s drawing and ask your building department before you buy.