How much glass weighs
Glass is heavier than it looks. Ordinary soda-lime float glass has a density of about 2,500 kg/m³, or 156 lb per cubic foot. That makes a single tabletop or shower panel a two-person job surprisingly quickly, and it matters when you choose hinges, shelf brackets, wall anchors or a window frame. The calculator gives the weight of one or several panels, single, double or triple glazed, and the weight per square foot.
The formula
- Weight = width × height × thickness × number of panes × density
- Rule of thumb: about 13 lb per square foot per inch of thickness, or 3.25 lb per square foot for 1/4 in glass
Tempered glass weighs the same as annealed glass of the same thickness. Laminated glass adds a thin plastic interlayer that changes the weight very little. Insulated units add spacers and sealant, but the glass is almost all of the weight.
Worked example: a glass tabletop
A 36 × 48 in tabletop in 1/4 in glass:
- Area: 36 × 48 = 1,728 sq in, or 12 sq ft.
- Weight per square foot: 3.25 lb.
- Weight: 12 × 3.25 = 39 lb (17.7 kg).
The same size in 1/2 in glass weighs 78 lb, which calls for heavy-duty supports and two people to move it.
Weight by thickness
For a 36 × 48 in panel:
| Thickness | Weight | Per sq ft |
|---|---|---|
| 1/8 in | 19.5 lb | 1.63 lb |
| 3/16 in | 29.3 lb | 2.44 lb |
| 1/4 in | 39.0 lb | 3.25 lb |
| 3/8 in | 58.5 lb | 4.88 lb |
| 1/2 in | 78.0 lb | 6.50 lb |
Typical thicknesses
- Picture frames and cabinet doors: 1/8 in (3 mm).
- Residential windows: two panes of 1/8 or 3/32 in in an insulated unit.
- Tabletops: 1/4 in for covers on another surface, 3/8 to 1/2 in for freestanding tops.
- Frameless shower doors: 3/8 or 1/2 in tempered glass; a 30 × 72 in door in 3/8 in weighs about 73 lb, so heavy-duty hinges are required.
- Glass railings and floors: laminated and tempered, sized by an engineer.
Handling safely
Wear cut-resistant gloves and long sleeves, carry large panels vertically, and use suction cup lifters for anything over about 50 lb or wider than your arm span. Never lay tempered glass on a hard edge or a stone: the edges are its weak point.