Both are frameless tempered glass. One weighs a third more, costs more, needs heavier hinges and shows more green. When the extra thickness is worth it and when it is not.
3/8-inch is the standard frameless shower glass and the right answer for most enclosures. 1/2-inch is for a door wider than about 30 inches, a fixed panel taller than about 78 inches without a header, or an owner who wants the thicker edge. The extra glass costs more, weighs a third more, needs heavier hinges and more backing in the wall, and shows more green unless it is low-iron. Choose 1/2 inch for a reason, not by default.
| Feature | 3/8″ (10 mm) | 1/2″ (12 mm) |
|---|---|---|
| Weight of a 30×72″ door | ~75 lb | ~100 lb |
| Stiffness | Adequate to ~30″ door width | Noticeably stiffer; doors to ~36″, tall fixed panels |
| Look | Standard frameless | Heavier edge; reads as substantial |
| Hinges required | Standard frameless hinges | Heavy-duty hinges, often three |
| Wall backing needed | Solid backing at hinges | Solid backing; more of it |
| Deflection on a tall fixed panel | Some flex on panels over ~78″ without a header | Minimal |
| Green tint (standard glass) | Visible at the edge | More visible; low-iron recommended |
| Cost | Baseline | Higher: more glass, heavier hardware |
| Where it suits | Most frameless enclosures | Wide doors, tall panels, a heavy look, no header |
In a frameless enclosure the glass is the structure: there is no frame to stiffen it, so the glass has to resist bending on its own. Stiffness rises with the cube of thickness, so 1/2-inch glass is more than twice as stiff as 3/8. That matters on a wide door, which twists on its hinges, and on a tall fixed panel, which flexes at the top when it is pushed. It does not matter on a 26-inch door in an alcove, where 3/8 is plenty and 1/2 is weight for its own sake.
The weight is the practical cost. A 3/8-inch door 30 by 72 inches weighs about 75 pounds; the same door in 1/2-inch weighs about 100. Hinges are rated for it — heavy-duty frameless hinges, usually three on a 1/2-inch door — but the hinges bolt through the tile into the wall, and the wall has to be solid where they land. If the hinge wall has blocking, either thickness works. If it does not, 3/8 with a header is the honest recommendation; see frameless shower doors.
Thicker glass reads as a heavier, more expensive edge, and some bathrooms want that. It also shows more green: the tint in standard float glass is proportional to the path length, so a 1/2-inch edge is greener than a 3/8-inch edge, and against white tile the difference is visible. Low-iron glass removes it and is worth specifying on any 1/2-inch enclosure with pale tile; on 3/8 it is a preference.
A single swing door over 30 inches wide. A fixed panel over 78 inches tall with no header bar and no return to stiffen it. A steam enclosure with a transom, where the panels are tall and closed at the top. A splash panel that stands alone with one edge in a channel and nothing else holding it. Everywhere else, 3/8 inch, with the money spent on coating and hardware instead. For the framed-versus-frameless question see the comparison.
Stiffer, heavier and more expensive. Better only where the stiffness is needed: doors over about 30 inches, tall unsupported panels, steam enclosures. For most enclosures 3/8 inch is the right glass.
About a third: a 30-by-72-inch door is roughly 75 pounds in 3/8 and 100 in 1/2. Both need solid backing in the hinge wall; 1/2 needs heavy-duty hinges.
Yes; the green in standard glass is proportional to thickness, and it shows at the edge. Low-iron glass removes it and is recommended on 1/2-inch enclosures with white tile.
Yes, and it is common: 1/2-inch fixed panel for stiffness, 3/8-inch door for weight on the hinges. The edges are polished to match.
1/2 inch: more glass, heavier hardware, sometimes low-iron on top. We quote after measuring rather than publish per-enclosure prices.
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
Send a photo and the door width. We will tell you 3/8 or 1/2, what the hinge wall needs, and quote.
