Glass shelves can add a modern touch to any room. Although glass shelves are sturdy, the fact that they are made of glass can lead people to worry about how much weight they can bear. The amount of weight a glass shelf can support varies depending on a number of factors. These include the type of glass, the thickness of the shelf and the amount of space between the brackets that hold it up. Calculating how much weight a glass shelf can support is a straightforward process.
Measure your shelves. You'll need to know the thickness of the glass as well as the length and depth of the shelf. The most common glass shelf sizes range between approximately 5 mm (3/16 in) and 13mm (1/2 in).
Determine what type of glass the shelves are made of. Some glass shelves are made of annealed glass, while others are made of tempered glass. Tempered glass is chemically treated to strengthen it and prevent it from breaking into dangerous pieces if it does shatter. Tempered glass is usually stronger and safer but is also more expensive than annealed glass.
Measure the distance between the supports you will be using to hold up the shelves. The closer the supports are to each other, the more weight the shelf as a whole will be able to support. For instance, a 122-cm annealed glass shelf 20 cm deep will be able to support around 21 kg if its supports are around 60 cm apart. By contrast, halving the distance between the supports to 30cm more than quadruples the weight limit to almost 90 kg.
Use an online weight calculator to determine the amount of weight your glass shelf can hold. Some examples are given in the Resources section below.
Because of slightly different assumptions about the characteristics of glass, different calculators may give slightly different results. Always use the lowest estimate.