Glass · Density
Glass density and unit weight
Float and toughened glass: 2500 kg/m³ (2.5 g/cm³, 156.1 lb/ft³), the figure in EN 572-1. As a unit weight that is 24.5 kN/m³, and as a weight per area 2.5 kg per m² for every millimetre of thickness (0.232 kg, 0.512 lb per square foot per mm): 10 mm glass weighs 25 kg/m², 2.32 kg per sq ft. The glass weight calculator uses the same figure for any pane, laminated make-up or insulating unit.
Glass density in every unit
| Unit | Soda-lime float and toughened glass |
|---|---|
| kg/m³ | 2500 |
| g/cm³ | 2.5 |
| lb/ft³ | 156.1 |
| Unit weight, kN/m³ | 24.52 |
| Per mm of thickness, kg/m² | 2.5 |
| Per mm of thickness, kN/m² | 0.0245 |
Weight by thickness, from the density
Weight per area = thickness × density. Toughened, annealed and heat-strengthened glass of the same thickness weigh the same.
| Thickness | kg/m² | kg per sq ft | lb per sq ft |
|---|---|---|---|
| 3 mm | 7.5 | 0.697 | 1.536 |
| 4 mm | 10.0 | 0.929 | 2.048 |
| 5 mm | 12.5 | 1.161 | 2.560 |
| 6 mm | 15.0 | 1.394 | 3.072 |
| 8 mm | 20.0 | 1.858 | 4.096 |
| 10 mm | 25.0 | 2.323 | 5.120 |
| 12 mm | 30.0 | 2.787 | 6.144 |
| 15 mm | 37.5 | 3.484 | 7.681 |
| 19 mm | 47.5 | 4.413 | 9.729 |
Laminated glass
The PVB interlayer is lighter than glass, about 1070 kg/m³, so a laminated pane weighs a little more than its glass alone: 4 + 4 mm with 0.76 mm PVB is 20.81 kg/m², 6 + 6 mm with 0.76 mm PVB 30.81 kg/m², 8 + 8 mm with 1.52 mm PVB 41.63 kg/m². The laminated glass weight page lists the usual make-ups.
Where the figure comes from
EN 572-1, the European standard for soda-lime silicate building glass, gives 2500 kg/m³ for float glass, and EN 12150 (toughened) and EN 14449 (laminated) build on the same glass. Low-iron (extra-clear) float glass is the same soda-lime family and is taken at the same figure. Special glasses differ (borosilicate and some fire-resistant glasses are lighter, lead glass much heavier): use the manufacturer's data sheet for those.
Questions people ask
- What is the density of glass in kg/m³?
- Soda-lime silicate glass, the float glass of windows and shower screens, is 2500 kg/m³ (2.5 g/cm³), the figure EN 572-1 gives. That is 2.5 kg per square metre for every millimetre of thickness: 10 mm glass weighs 25 kg/m².
- Is toughened glass denser than normal glass?
- No. Toughening (tempering) heats and quenches the same float glass; the density stays at 2500 kg/m³, so a toughened pane weighs the same as an annealed one of the same size and thickness.
- What is the unit weight of glass in kN/m³?
- 2500 kg/m³ × 9.81 m/s² = 24.5 kN/m³, the value used for the self-weight of glazing in load calculations; per millimetre of thickness that is 0.0245 kN/m², about 0.025 kN/m².