Glass is heavier than it looks: a standard 6 mm window pane weighs 15 kg per square metre, and a large tempered tabletop or shower screen can easily exceed what one person should lift. Knowing the weight helps choose hinges, brackets, clamps and the number of installers, and estimate shipping.
How to use the Glass Weight Calculator
- Material
- Custom density
- Shape
- Length (or diameter)
- Width
- Thickness
- Quantity
- Every result field is editable: type into Weight of one piece or any other result and Thickness plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
The calculator finds the face area of the shape, multiplies by the thickness for the volume and by the material density for the weight. The weight per unit area is handy for checking floor, shelf or wall loads.
Densities used
| Material | kg/m³ | lb/ft³ | kg/m² per mm |
|---|---|---|---|
| Window / float glass (soda-lime) | 2,500 | 156.1 | 2.50 |
| Tempered glass | 2,500 | 156.1 | 2.50 |
| Laminated glass | 2,500 | 156.1 | 2.50 |
| Borosilicate (Pyrex) | 2,230 | 139.2 | 2.23 |
| Lead crystal | 3,100 | 193.5 | 3.10 |
| Fused quartz / silica | 2,200 | 137.3 | 2.20 |
| Fire glass (tempered) | 2,500 | 156.1 | 2.50 |
Good to know
Rule of thumb: soda-lime glass weighs 2.5 kg per m² per mm of thickness (about 13 lb per ft² per inch).
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Material | Choose one: Window / float glass (soda-lime), Tempered glass, Laminated glass, Borosilicate (Pyrex) … |
| Custom density | Units: kg/m³, lb/ft³, g/cm³, lb/yd³ |
| Shape | Choose one: Rectangle / square, Circle (length = diameter), Right triangle |
| Length (or diameter) | Units: m, ft, cm, in, yd |
| Width | Units: m, ft, cm, in, yd |
| Thickness | Units: mm, in, cm |
| Quantity | A number |
Formula
Weight = area × thickness × density × quantityArea: rectangle L × W, circle π D² ÷ 4, triangle L × W ÷ 2Worked example
Inputs — Material: Window / float glass (soda-lime); Custom density: 2,500 kg/m³; Shape: Rectangle / square; Length (or diameter): 1.2 m; Width: 0.9 m; Thickness: 6 mm; Quantity: 1.
Results — Area of one piece = 1.08 m²; Volume of one piece = 6.48 L; Weight of one piece = 16.2 kg; Total weight = 16.2 kg; Weight per unit area = 15 kg/m².
Frequently asked questions
How much does glass weigh per square foot?
About 3.2 lb/ft² for ¼ in (6 mm) glass, 2.4 lb/ft² for 3/16 in and 1.6 lb/ft² for ⅛ in.
What is the weight of glass per m² per mm?
2.5 kg/m² for every millimetre of thickness for ordinary soda-lime glass.
Is tempered glass heavier?
No – tempering changes the strength, not the density.
What formula does the Glass Weight Calculator use?
Weight = area × thickness × density × quantity.