# Shower Door Towel Bars: Sizes, Back-to-Back Sets & How They Mount | IDEAL Shower Doors

URL: https://idealshowerdoors.com/store/guide/shower-door-towel-bars
Description: Glass shower door towel bars explained: single-sided vs back-to-back, towel bar and handle sets, sizes from 12" to 30" center to center, mounting through 1/2" holes, glass thickness and choosing a size. From IDEAL Shower Doors.
Seller: IDEAL Shower Doors, Danvers, MA (https://idealshowerdoors.com/store/)

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Guide

# Shower Door Towel Bars: Sizes, Back-to-Back Sets & How They Mount

By the [IDEAL install crew](https://idealshowerdoors.com/) · Frameless glass showers in Massachusetts and New Hampshire since 2014 · Updated 10-20-2026

A shower door towel bar bolts through 1/2" (12 mm) holes in the glass and is sized center to center, usually 18" or 24". Pick a single-sided bar for one side of the glass, a back-to-back bar for a towel bar on both sides, or a towel bar & handle set when the door needs a pull on the inside and a towel bar on the outside.

A towel bar & handle set from the outside: the towel bar runs level between holes 1 and 2. On the shower side, the pull handle hangs straight down from the towel bar's end post at hole 2 to a third hole 6" or 8" below. Shown: an 8" pull with an 18" bar (CRL BM8X18).

A towel bar is sized by the spacing of its mounts (center to center), but the bar itself is longer. CRL's 24" ladder style towel bar is 24" center to center and 28" overall, so leave room for the ends.

## Can you put a towel bar on a glass shower door?

Yes. Glass-mount towel bars bolt through holes in the glass, on the door or on a fixed panel. They are made for monolithic tempered glass, and like a handle they need holes that were cut before the glass was tempered. If your glass already has holes for a towel bar, a new bar with the same spacing goes right back in. If it has no holes, you can't add a through-glass bar to that piece of glass.

## Towel bar or towel bar & handle set?

- **[Single-sided towel bar](https://idealshowerdoors.com/store/p/bm24ch):** one bar on one side of the glass, with slim end caps on the other side (3/16" on CRL's [BM Series](https://idealshowerdoors.com/store/p/bm24ch), 1/8" on the no-washer [BMNW Series](https://idealshowerdoors.com/store/p/bmnw18ch)). Good on a fixed panel, and the low caps make them a good fit on bypass sliding doors too. See them all in [Towel Bars](https://idealshowerdoors.com/store/c/towel-bars#towel-bars).
- **[Back-to-back towel bar](https://idealshowerdoors.com/store/p/bm18x18ch):** a matching bar on each side, bolted to each other through the same holes, so there is a towel bar inside and out. Most styles come both ways in [Towel Bars](https://idealshowerdoors.com/store/c/towel-bars#towel-bars).
- **[Towel bar & handle set](https://idealshowerdoors.com/store/c/towel-bars#towel-bar-handle-sets):** a pull handle on the shower side and a towel bar on the outside. One door gives you a handle to open it from inside and a place to hang a towel outside. The towel bar runs level through two holes. On the shower side, the pull hangs **straight down** from one of the towel bar's end posts, sharing that hole, to a third hole 6" or 8" below it. That is three holes in all: for [an 8" pull with an 18" bar](https://idealshowerdoors.com/store/p/bm8x18ch), two holes 18" apart and a third 8" below one of them. See all [towel bar & handle sets](https://idealshowerdoors.com/store/c/towel-bars#towel-bar-handle-sets).
- **[Towel bar & knob set](https://idealshowerdoors.com/store/p/tbct18bn):** a towel bar on one side and a knob on the other. The knob threads into one end post of the bar through the same hole, so it needs only the bar's two holes, like CRL's 18" towel bar and traditional knob set. Also in [Towel bar & handle sets](https://idealshowerdoors.com/store/c/towel-bars#towel-bar-handle-sets).

## What sizes do shower door towel bars come in?

Towel bars are sized center to center, the spacing of the two holes. These are the sizes in our [Towel Bars](https://idealshowerdoors.com/store/c/towel-bars) section; you can filter it by size and type.

| Type | Center to center sizes |
| --- | --- |
| **Single-sided** ([BM](https://idealshowerdoors.com/store/p/bm24ch) / [BMNW](https://idealshowerdoors.com/store/p/bmnw18ch) tubular) | 12", 18", 20", 22", 24", 26", 27", 28", 30" |
| **Back-to-back** ([BM tubular](https://idealshowerdoors.com/store/p/bm18x18ch)) | 12", 18", 20", 24", 30" |
| **[Square](https://idealshowerdoors.com/store/p/sq24x24ch), [mitered](https://idealshowerdoors.com/store/p/mt24x24ch), [ladder](https://idealshowerdoors.com/store/p/ltb24x24ch), [oval/round](https://idealshowerdoors.com/store/p/0r24x24ch), [Colonial](https://idealshowerdoors.com/store/p/c0l24x24pn)** | Mostly 18" and 24" |
| **[Towel bar & handle sets](https://idealshowerdoors.com/store/c/towel-bars#towel-bar-handle-sets)** | 6" or 8" pull with a 12", 18", 20", 22" or 24" bar |
| **[Premium U-style](https://idealshowerdoors.com/store/p/htb24usb)** (concealed hardware) | 24", for 3/8" glass |

## How do I choose the right size for my door?

The center to center size is the hole spacing, but the bar is longer than that. CRL's ladder style bars, for example, are 22" overall at [18" center to center](https://idealshowerdoors.com/store/p/ltb18ch) and 28" overall at [24"](https://idealshowerdoors.com/store/p/ltb24ch). So:

1. **Replacing a bar?** Measure from the middle of one post to the middle of the other, and order that size. The holes are already in the glass, so the spacing has to match exactly.
2. **New glass?** Choose the bar first, then have the holes laid out for it before the glass is tempered. Keep the bar's full overall length clear of the hinges, clamps, handle and the edges of the glass.
3. **Check the swing.** On a door, make sure the bar's ends and posts won't hit a wall, panel or the other hardware when the door opens.

On a typical door, 18" and 24" are the sizes CRL stocks in nearly every style, which makes them the easiest to match across a whole shower.

## How does a towel bar mount through the glass?

Each post bolts through a **1/2" (12 mm)** hole. CRL's BM bars use 1/4"-20 threads, and plastic washers keep the metal from touching the glass. Bars with **metal washers** add a 1-1/4" (32 mm) decorative washer at each post that also covers small chips around the hole; the **no-washer** versions ([BMNW](https://idealshowerdoors.com/store/p/bmnw18ch)) give a sleeker, continuous look. CRL's towel bar & handle sets come with all the hardware needed to install them.

## What glass thickness do I need?

Most CRL towel bars fit glass from **1/4" to 1/2"** (6 to 12 mm). Ladder style bars need 5/16" to 1/2", and the [premium U-style bar](https://idealshowerdoors.com/store/p/htb24usb) is made for 3/8" glass only. [Here's how to measure your glass](https://idealshowerdoors.com/store/measure).

## Matching the towel bar to your handle

Stay in the same series and finish as the handle: BM tubular with BM, square SQ with SQ, mitered MT with MT, ladder with ladder. The [sets](https://idealshowerdoors.com/store/c/towel-bars#towel-bar-handle-sets) take the guesswork out of it, since the pull and the bar come together in one finish. The most common finishes are polished chrome, brushed nickel, matte black, oil rubbed bronze and polished nickel. Need a grab bar instead? A towel bar on the glass isn't one. CRL's grab bars mount to the shower wall, not the glass; they are in [Pull Handles & Knobs](https://idealshowerdoors.com/store/c/pulls-knobs#grab-bars).

## Where we'd start

- [CRL BM24](https://idealshowerdoors.com/store/p/bm24ch): 24" single-sided tubular towel bar, from CRL's most popular towel bar series.
- [CRL BM18X18](https://idealshowerdoors.com/store/p/bm18x18ch): 18" back-to-back tubular bar, from CRL's most popular back-to-back series. Also in [24"](https://idealshowerdoors.com/store/p/bm24x24ch).
- [CRL BM8X18](https://idealshowerdoors.com/store/p/bm8x18ch): 8" pull inside, 18" towel bar outside, with metal washers.
- [CRL BMNW8X18](https://idealshowerdoors.com/store/p/bmnw8x18ch): the same set without metal washers, for a sleeker look.
- [CRL SQ24X24](https://idealshowerdoors.com/store/p/sq24x24ch): 24" square back-to-back bar to match square-cornered hinges.

Choosing the handle too? Read [how to choose a shower door handle](https://idealshowerdoors.com/store/guide/how-to-choose-a-shower-door-handle).

## Products in this guide

- [CRL BM24CH 24" Single-Sided Tubular Towel Bar 10 finishes from $42.15 View](https://idealshowerdoors.com/store/p/bm24ch)
- [CRL BM18X18CH 18" Back-to-Back Tubular Towel Bar 10 finishes from $67.15 View](https://idealshowerdoors.com/store/p/bm18x18ch)
- [CRL BM24X24CH 24" Back-to-Back Tubular Towel Bar 8 finishes from $84.67 View](https://idealshowerdoors.com/store/p/bm24x24ch)
- [CRL BM8X18CH 8" Pull Handle and 18" Towel Bar Set 10 finishes from $61.31 View](https://idealshowerdoors.com/store/p/bm8x18ch)
- [CRL BMNW8X18CH 8" Pull Handle and 18" Towel Bar Set (No Metal Washers) 4 finishes from $59.85 View](https://idealshowerdoors.com/store/p/bmnw8x18ch)
- [CRL SQ24X24CH 24" Back-to-Back Square Towel Bar 6 finishes from $146.89 View](https://idealshowerdoors.com/store/p/sq24x24ch)
- [CRL LTB24X24CH 24" Back-to-Back Ladder Style Towel Bar 5 finishes from $144.29 View](https://idealshowerdoors.com/store/p/ltb24x24ch)
- [CRL TBCT18BN 18" Towel Bar and Traditional Knob Set 2 finishes from $82.95 View](https://idealshowerdoors.com/store/p/tbct18bn)

## Common questions

**What size towel bar should I put on a shower door?**

18" and 24" center to center are the most common sizes, and CRL stocks nearly every towel bar style in both. If you are replacing a bar, match the spacing of the holes already in the glass.

**How are shower door towel bars measured?**

Center to center: from the middle of one mounting post to the middle of the other, which is the spacing of the holes. The bar itself is longer than that.

**Can I add a towel bar to my existing glass shower door?**

Only if the glass already has holes in the right places. Shower glass is tempered and can't be drilled after it is made, so the holes have to be cut before tempering.

**What is the difference between a back-to-back and a single-sided towel bar?**

A back-to-back bar puts a matching towel bar on each side of the glass, bolted through the same holes. A single-sided bar is on one side only, with slim end caps on the other.

**What is a towel bar and handle set?**

A combination with a pull handle on the inside of the door and a towel bar on the outside, in matching finishes, with all the mounting hardware included. The towel bar mounts level through two holes; the pull hangs straight down from one end of the bar, sharing that hole, to a third hole 6" or 8" below, so the set uses three holes.

**What size hole does a shower door towel bar need?**

Most CRL glass-mount towel bars need 1/2" (12 mm) holes and fit glass from 1/4" to 1/2" thick.

## More guides

[**Glass clamp types & how to measure** A shower glass clamp either holds a fixed panel to the wall, floor or ceiling (wall-to-glass) or joins two panels together (glass-to-glass) at 90°, 135° or 180°.](https://idealshowerdoors.com/store/guide/shower-glass-clamp-types)[**Shower door hinge types** Frameless shower door hinges come in three types: wall mount hinges that screw to the wall, glass-to-glass hinges that hold the door to a fixed glass panel at 180°, 135° or 90°, and pivot hinges that hold the door at its top and bottom corners.](https://idealshowerdoors.com/store/guide/shower-door-hinge-types)[**How to replace a shower door hinge** To replace a shower door hinge, buy one that fits the cut-out already in your glass, your glass thickness and the way your door hangs.](https://idealshowerdoors.com/store/guide/how-to-replace-a-shower-door-hinge)[**Square vs. beveled hinges and clamps** Square hinges and clamps have flat sides and crisp corners.](https://idealshowerdoors.com/store/guide/square-vs-beveled-shower-door-hinges)