# How to Measure Shower Door Glass Thickness (with Pictures) | IDEAL Shower Doors

URL: https://idealshowerdoors.com/store/measure
Description: Measure your glass shower door thickness in a minute: tape measure method, common sizes (1/4", 5/16", 3/8", 1/2") and how to measure the gap for a replacement seal.
Seller: IDEAL Shower Doors, Danvers, MA (https://idealshowerdoors.com/store/)

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Guide

# How to Measure Shower Door Glass Thickness

By the [IDEAL install crew](https://idealshowerdoors.com/) · Frameless glass showers in Massachusetts and New Hampshire since 2014 · Updated 10-04-2026

Every clip-on shower door seal is made for one glass thickness, so this is the one measurement you need before you order. It takes about a minute with a tape measure.

**Quick answer:** Most frameless glass shower doors are **3/8" (10 mm)** or **1/2" (12 mm)** thick. Older and framed doors are often **1/4" (6 mm)**. Some European-style doors are ** 5/16" (8 mm)**.

Step 1. Open the door and find a bare edge of the glass, away from hinges and handles.

Step 2. Lay a tape measure flat across the edge and count the 1/16" marks. Six marks = 3/8". Eight marks = 1/2".

Step 3. Compare your reading to the four standard sizes. 3/8" is the most common for frameless doors; 1/2" is the heavy, high-end glass.

Measure the gap too: close the door and measure from the bottom of the glass to the curb (or to the wall or panel for side seals). Pick a seal whose suggested gap matches.

## Common shower glass thicknesses

| Thickness | Metric | Where you'll find it |
| --- | --- | --- |
| **[1/4"](https://idealshowerdoors.com/store/glass/1-4-inch)** | 6 mm | Framed doors, older enclosures, some sliders |
| **[5/16"](https://idealshowerdoors.com/store/glass/5-16-inch)** | 8 mm | Some semi-frameless and imported doors |
| **[3/8"](https://idealshowerdoors.com/store/glass/3-8-inch)** | 10 mm | The most common frameless swing door |
| **[1/2"](https://idealshowerdoors.com/store/glass/1-2-inch)** | 12 mm | Heavy, high-end frameless doors and panels |

## Tips for an accurate measurement

- Measure the glass itself, not a seal, clamp or hinge that's covering the edge. Slide an old seal off first if you need to.
- Measure in two or three places; the reading should be the same everywhere.
- If you land between two sizes, it's almost always the closer standard size above (for example, a hair under 3/8" is 3/8").
- Seals that tape to the glass edge or wall (bulb, fin, L and V seals) don't depend on glass thickness: choose those by the gap.

## Next step

Once you know your glass thickness, the Seal Finder shows only the seals that fit, or use our guide to match the leak to the seal.

[Use the Seal Finder](https://idealshowerdoors.com/store/finder)[Which seal do I need?](https://idealshowerdoors.com/store/guide/which-seal)

- [Not sure which seal you need? Use our Seal Finder Pick your door, point to where it leaks and we'll show only the seals that fit your glass. Takes about 30 seconds. Start the Seal Finder →](https://idealshowerdoors.com/store/finder)