Glass Thickness Guide

Glass is manufactured in a wide range of thicknesses for various applications. In addition to the type of glass, the edgework of the glass, and the style of design, careful consideration must be given to the thickness of glass. While local building codes must always be consulted, several options exist depending on the glass’s application and use. Armed with the knowledge below, a savvy customer will be better prepared to navigate the choices surrounding glass thickness.

Single Lite - The industry term for what is commonly known as a “single pane” piece of glass, single lite glass is utilized for most interior applications (such as shelves, cabinets, mirrors, and tabletops) as well as in the exteriors of older buildings. Single lite glass does not carry the enhanced insulating or “energy saving” properties (or R-Value) of Insulated Glass, and is therefore discouraged for new construction and contemporary remodels.

Insulated Glass - Often called “double pane” glass, insulated glass (IG) units consist of two pieces of single lite glass separated by an aluminum spacer of various thicknesses, and joined together at the glass factory. IG units provide greatly enhanced R-Values, and are a savvy choice to reduce expensive long-term heating or cooling costs for the home or business. Beware of contractors who say they can build IG units themselves: ONLY insulated glass units made in a factory carry a warranty against internal fogging or moisture build-up due to failure. IGs typically carry a 10-year warranty from the manufacturer. Due to this warranty, IG replacement will always replace both “panes” of glass, even if only one is damaged.

1/8 Inch Glass - Most commonly used in picture frames and other small display items, 1/8” glass is visibly very thin. Because 1/8” glass is relatively fragile, it is not utilized in modern commercial or residential exterior construction, as even minor impacts such as those from small birds are likely to cause damage.

¼ Inch Glass - Typically utilized in garage door windows and on top of tables, ¼” glass provides an attractive confluence of strength and economical price point. Much less heavy and expensive than thicker glass, ¼” glass still offers the strength needed to set down a metal cup on a coffee table without worrying. Mirrors are typically ¼” thick. 

3/8 Inch Glass - Shower doors and exterior furniture often utilize 3/8” glass due to its enhanced strength. While significantly more expensive and heavier than standard 1/4” glass, homeowners often use 3/8” glass in applications such as patio tables, where dangers such as falling acorns or a child’s or dog’s toy may impact it.

½ Inch Glass - Commonly used in interior applications such as shower doors, ½” glass is HEAVY. It is also significantly stronger than thinner glass, and for that reason may also be used for specialty displays (such as a glass cabinet, or a shelf that holds heavy statues or decorations). While the strength of ½” glass may be attractive, one must also balance the price and ease of relocation (it is heavy) when selecting interior glass.

¾ Inch Glass and Above - Sometimes utilized in shower doors, ¾”, 5/8” and 1” glass is uncommon due to its weight and expense. ¾” glass and above is mostly seen in shower doors. Glass thicknesses of 1” or greater are almost never utilized outside of specialty commercial applications, such as airports.

Laminated Glass - Any thickness of glass may be filmed or laminated for increased strength, durability, or safety. Laminated or filmed glass is a specialty product, and is most often selected when certain specialty criteria are specified, such as for protection from windborne debris inside hurricane or tornado zones. Laminated glass may also hold special properties such as reducing the sun’s radiation, or providing privacy for a gym or office; however, laminated glass often costs significantly more than non-laminated glass, due to the greater manpower used in its creation.

Glass thicknesses measured in millimeters (mm) may be encountered. While construction in the United States typically utilizes the American System of measuring (seen above in fractions of an inch), most locales outside of the U.S. use the Metric System (based on the millimeter). If you do happen to encounter a glass thickness shown in millimeters, an easy conversion formula can be used to convert from millimeters to inches: Divide the millimeter number by 25.4. E.G. 6mm divided by 25.4 = 0.23622 inches, or 1/4” when rounded.

While one must consider many variables when selecting the appropriate type and thickness of glass, this guide may aid the discerning homeowner or general contractor in selecting the appropriate thickness of glass for their project and pricepoint. And if you’re still not quite sure about which thickness of glass to select, the friendly glaziers and staff at A-1 Glass & Mirror are happy to offer our expertise and experience.