Glass Size Calculator
Enter the pane width and height, the thickness and the type of glass. The calculator gives the area, the weight, the minimum thickness for a framed window pane, the people needed to carry it and whether safety glass is needed.
- Glass weight
- Thickness
- Safety glass
Thickness guides are for framed vertical glazing. Overhead and structural glass needs specialist design.
Glass weighs 2.5 kg per square metre for every millimetre of thickness. A 1,200 × 1,000 mm pane of 6 mm glass is 1.2 m² and weighs 18 kg. Larger panes need thicker glass. Doors, low windows and bathrooms need toughened or laminated safety glass.
Glass weight chart
Per square metre. Search for a thickness.
| Thickness (mm) | kg per m² | lb per sq ft | Typical use |
|---|---|---|---|
| 3 | 7.5 | 1.54 | Picture frames |
| 4 | 10 | 2.05 | Small windows |
| 6 | 15 | 3.07 | Doors, larger windows |
| 8 | 20 | 4.1 | Shelves, tabletops |
| 10 | 25 | 5.12 | Shower screens, tables |
| 12 | 30 | 6.14 | Balustrades |
| 15 | 37.5 | 7.68 | Large partitions |
2.5 kg per m² per mm.
Pane width and glass
1,200 mm high window. Slide the width.
The pane and its edge thickness are drawn to scale.
How to choose glass
Size to thickness. Step through it.
Measure
W × H.
Order toughened glass to the exact finished size. It cannot be cut afterwards.
Float, toughened or laminated
Glass types. Compare them.
Standard.
Safety.
Safety.
Laminated glass also blocks most UV and cuts noise.
Before ordering
Glass checks. Tick each item.
Tick each item as you go.
Lift large panes with suction lifters and wear cut-resistant gloves.
What you get
Glass sizing. Each tile explains one result.
kg and lb.
m².
Minimum.
Safety.
People.
One person can safely carry about 25 kg of glass.
Frequently Asked Questions
No question matches that search.
How much does glass weigh?
Two and a half kilograms per square metre for each millimetre of thickness.
How thick should window glass be?
Four millimetres for small panes, rising to six or eight for large ones.
Where is safety glass needed?
In doors, low windows near the floor, bathrooms and anywhere people might fall against it.
Can toughened glass be cut?
No. It must be cut to size before it is toughened.
What thickness for a glass tabletop?
Usually eight to ten millimetres, toughened.
What is laminated glass?
Two sheets bonded with a plastic layer that holds the pieces if it breaks.
How do I carry a large glass pane?
Upright, with gloves and suction lifters, and enough people for the weight.
The right pane, safely
Know the weight and the thickness before you order, and choose safety glass wherever people could touch it.
More size calculators
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