Shower Door Glass Thickness Chart
Quick answer
US shower doors use five glass thicknesses: 3/16 in (4.8 mm) on framed sliders, 1/4 in (6.35 mm) on framed and light frameless panels, 5/16 in (8 mm) on semi-frameless doors, 3/8 in (9.5 mm) — the frameless standard, and 1/2 in (12.7 mm) on heavy premium doors. Replacement seals are sized to these classes, so identify yours before buying anything.
Last updated: · Data reviewed: · Source: C.R. Laurence technical resources
The chart
| Thickness | Metric twin | Typical doors | Press-on seal availability |
|---|---|---|---|
| 3/16 in (0.1875) | 5 mm (4.76 mm exact) | Framed sliding tub/shower doors | Rare — use framed slide-in inserts instead |
| 1/4 in (0.25) | 6 mm (6.35 mm exact) | Framed, semi-frameless, light frameless sliders | Wide: sweeps, side, magnetic seals |
| 5/16 in (0.3125) | 8 mm (7.94 mm exact) | Semi-frameless hinged, mid-weight sliders | Moderate — often dual 5/16–3/8 in channels |
| 3/8 in (0.375) | 10 mm (9.53 mm exact) | Frameless hinged (US standard) | Widest of all sizes |
| 1/2 in (0.5) | 12 mm (12.7 mm exact) | Premium heavy frameless, steam doors | Good — dedicated 1/2 in channels |
How to read a listing's size range
Listings state either one size (“for 3/8 in glass”) or a range (“fits 5/16–3/8 in / 8–10 mm”). Single-size rigid channels fit exactly that class. Range channels are flexible: snug at the small end, neutral at the large end — the practical answer for 5/16 in glass, which has fewer dedicated products. What never works is spanning a full 1/8 in class: no honest “3/8 in” channel also fits 1/2 in glass.
Full fraction → mm conversion
| Fraction | Decimal (in) | Millimeters | Note |
|---|---|---|---|
| 1/16″ | 0.0625 | 1.60 | |
| 1/8″ | 0.1250 | 3.20 | Common gap size |
| 3/16″ | 0.1875 | 4.80 | Common glass thickness |
| 1/4″ | 0.2500 | 6.40 | Common glass thickness / common gap size |
| 5/16″ | 0.3125 | 7.90 | Common glass thickness |
| 3/8″ | 0.3750 | 9.50 | Common glass thickness / common gap size |
| 7/16″ | 0.4375 | 11.10 | |
| 1/2″ | 0.5000 | 12.70 | Common glass thickness / common gap size |
| 9/16″ | 0.5625 | 14.30 | |
| 5/8″ | 0.6250 | 15.90 | |
| 11/16″ | 0.6875 | 17.50 | |
| 3/4″ | 0.7500 | 19.10 | Common gap size |
| 13/16″ | 0.8125 | 20.60 | |
| 7/8″ | 0.8750 | 22.20 | |
| 15/16″ | 0.9375 | 23.80 | |
| 1″ | 1.0000 | 25.40 | Common gap size |
Fraction to decimal converter
Enter a fraction like 3/8 or a decimal.
Identify your class in 60 seconds
Caliper the bare edge (method details in the measuring guide) and match: 6.3–6.4 mm → 1/4 in · 7.8–8.0 mm → 5/16 in · 9.4–9.6 mm → 3/8 in · 12.6–12.8 mm → 1/2 in. Then jump straight to the matching size page: 1/4 in, 5/16 in, 3/8 in, or 1/2 in.
Where thickness shopping goes wrong
- Treating 8 mm as 3/8 in — it is 5/16 in; the 1/16 in difference is a loose seal.
- Buying “universal” channels that claim to fit everything; channels physically cannot.
- Assuming the fixed panel matches the door on a door-plus-panel unit.
- Confusing tempered marking stamps (which note mm) with the frame's model number.
Frequently asked questions
What is the most common shower door glass thickness?
For frameless hinged doors, 3/8 inch (9.5 mm) is the US standard. Across all door styles including framed units, 1/4 inch is the most widespread.
Is thicker shower glass better?
Thicker glass is stiffer and feels more solid, but it is heavier — hinges sag sooner without quality hardware. For seals it is neither better nor worse; it just sets which channel size you buy.
Can a 3/8 inch seal fit 1/2 inch glass?
No. The channel is 1/8 inch too narrow; forcing it risks splitting the vinyl or chipping the glass edge. Buy the 1/2 inch version of the same profile.
My tempered stamp says 10 mm — which seals do I buy?
10 mm is the metric twin of 3/8 inch (9.53 mm). Choose seals listed for 3/8 in, preferring ones that state a 3/8 in / 10 mm range if the channel is rigid.