Do you want to order, install or replace glass? Then it is useful to know in advance how much the glass plate weighs. Glass quickly becomes heavy, especially with large windows, table tops, shower walls and insulating glass. The short rule is: glass weighs approximately 2.5 kilos per square meter per millimeter of glass thickness. This allows you to calculate the weight of almost any glass plate with one simple formula:
breedte (m) × hoogte (m) × glasdikte (mm) × 2,5 = gewicht in kg
In this article we explain how to calculate glass weight, what the different glass types and applications weigh, how to approach the weight of insulating glass and what you should pay attention to during transport and installation.
Rule of thumb: glass weighs approximately 2.5 kg/m² per mm of glass thickness. With insulating glass (HR++, triple) you only count the glass panes — the cavity weighs virtually nothing.
Why is the weight of glass important?
Glass weight is more important than many people think. You can easily lift a small mirror or window, but larger glass plates quickly become heavy. The weight determines, among other things:
- How many people are needed to lift the glass
- Whether the frame can support the glass
- Whether the hinges are strong enough
- Which batter you need
- Whether a table base is sturdy enough
- How to transport the glass safely
- Whether installation with glass pistons is necessary
- Whether additional support is needed
Especially with custom glass, you want to know this in advance. A glass plate that proves to be too heavy for the fittings or frame can be dangerous.
How much does glass weigh per m²?
Glass weighs on average approximately 2.5 kg per m² per mm of glass thickness. This applies to ordinary float glass and most single types of glass.
| Glass thickness | Weight per m² |
|---|---|
| 4 mm | ± 10 kg |
| 5 mm | ± 12.5 kg |
| 6 mm | ± 15 kg |
| 8 mm | ± 20 kg |
| 10 mm | ± 25 kg |
| 12 mm | ± 30 kg |
| 15 mm | ± 37.5 kg |
| 19 mm | ± 47.5 kg |
A sheet of glass 10 mm thick therefore weighs approximately 25 kg per square meter. This quickly increases with large sizes. Don't know yet what thickness you need? Then read which glass thickness you should choose.
Formula to calculate glass weight
You calculate the glass weight with this formula:
breedte (m) × hoogte (m) × glasdikte (mm) × 2,5 = gewicht (kg)
Example: a glass plate is 1000 mm wide, 2000 mm high and 8 mm thick. Converted, this is 1.0 meters wide, 2.0 meters high and 8 mm thick:
1,0 × 2,0 × 8 × 2,5 = 40 kg
This glass plate therefore weighs approximately 40 kilos. Are you still measuring? Then first read how to measure glass correctly.
Example glass weight calculations
| Dimension | Thickness | Calculation | Weight |
|---|---|---|---|
| 500 × 500 mm | 4 mm | 0.5 × 0.5 × 4 × 2.5 | 2.5kg |
| 1000 × 1000 mm | 6 mm | 1×1×6×2.5 | 15kg |
| 1000 × 2000 mm | 8 mm | 1×2×8×2.5 | 40kg |
| 1200 × 2200 mm | 10 mm | 1.2 × 2.2 × 10 × 2.5 | 66kg |
| 1500 × 2500 mm | 12 mm | 1.5 × 2.5 × 12 × 2.5 | 112.5kg |
For large glass plates, installation with two or more people is often necessary.
Weight per glass type
Weight of single glass
Single glazing consists of one pane of glass. You calculate the weight directly with the standard formula.
| Single glazing | Weight per m² |
|---|---|
| 4 mm | ± 10 kg |
| 5 mm | ± 12.5 kg |
| 6 mm | ± 15 kg |
| 8 mm | ± 20 kg |
| 10 mm | ± 25 kg |
Single glass of 4 mm is often used for small windows, cabinet glass or simple applications. You use thicker single glass for interior glass, table tops or heavy applications such as walkable glass, which weighs considerably due to its thick structure. You can order via custom glass.
Weight of tempered glass
Tempered glass weighs the same as normal glass of the same thickness. The tempering process makes the glass stronger and safer if broken, but not lighter.
| Tempered glass | Weight per m² |
|---|---|
| 6 mm | ± 15 kg |
| 8 mm | ± 20 kg |
| 10 mm | ± 25 kg |
| 12 mm | ± 30 kg |
A shower wall made of 10 mm tempered glass of 1000 × 2000 mm therefore weighs: 1 × 2 × 10 × 2,5 = 50 kg. That's quite heavy. Therefore, the wall, floor and stabilizing bar must be suitable. More about the difference between tempered or laminated glass.
Weight of laminated glass
Laminated glass consists of two or more panes of glass with foil in between. The weight is mainly determined by the glass layers; the foil only counts to a limited extent. Example: 33.1 laminated glass consists of two glass plates of 3 mm with one foil — together approximately 6 mm glass, so 6 × 2,5 = 15 kg per m².
| Laminated glass | Glass thickness together | Weight per m² |
|---|---|---|
| 33.1 | 6 mm | ± 15 kg |
| 44.1 | 8 mm | ± 20 kg |
| 55.1 | 10 mm | ± 25 kg |
| 66.2 | 12 mm | ± 30 kg |
| 88.2 | 16 mm | ± 40 kg |
Laminated glass can become quite heavy for balustrades, roof glass and fall protection.
Weight of mirrors
Mirror glass weighs about the same as normal glass of the same thickness.
| Mirror | Weight per m² |
|---|---|
| 4 mm | ± 10 kg |
| 6 mm | ± 15 kg |
A bathroom mirror measuring 800 × 1200 mm in 6 mm weighs: 0,8 × 1,2 × 6 × 2,5 = 14,4 kg. For larger mirrors, always use suitable mirror kit or mirror mounting and check whether the wall is strong enough.
Calculate the weight of insulating glass
With insulating glass, you add the glass plates together. The cavity (the air or gas space) is not counted as glass weight. The total package thickness is therefore not the same as the glass thickness for the weight.
Weight of HR++ glass
HR++ glass consists of two panes of glass with a cavity between them. Example: a HR++ pane with structure 4-15-5 consists of 4 mm glass, 15 mm cavity and 5 mm glass — together 9 mm glass:
9 × 2,5 = 22,5 kg per m²
The total thickness is 24 mm, but the weight is determined by the 4 mm and 5 mm glass plates. The cavity therefore does not count as glass thickness. View the full range insulating glass.
Weight of triple glass
Triple glazing consists of three glass plates and two cavities. Here too, you mainly add up the glass plates. Example: structure 4-12-4-12-4 consists of three glass plates of 4 mm — together 12 mm glass:
12 × 2,5 = 30 kg per m²
Triple glass is therefore often heavier than HR++ glass. This is important for existing window frames, revolving windows and doors.
Weight of vacuum glass
Vacuum glass is thinner than HR++ glass or triple glass. It usually consists of two sheets of glass with a very thin vacuum space between them. The weight depends on the glass thicknesses in the structure and is often relatively favorable, especially compared to triple glazing. Example: vacuum glass with a combined glass thickness of 8 mm weighs approximately 8 × 2,5 = 20 kg per m². That makes vacuum glass interesting for old window frames where weight and thickness are important.
Calculation examples for insulating glass
| Type | Construction | Glass thickness together | Weight per m² |
|---|---|---|---|
| HR++ | 4-15-4 | 8 mm | 20kg |
| HR++ | 4-15-5 | 9 mm | 22.5kg |
| Triple | 4-12-4-12-4 | 12 mm | 30kg |
| Triple | 4-12-4-12-6 | 14 mm | 35kg |
Do you want thicker insulating glass in an existing frame? Read thicker insulating glass in an existing frame.
Glass weight per application
Weight of shower walls
Shower walls are usually made of 8 or 10 mm tempered glass.
| Shower wall size | Thickness | Weight |
|---|---|---|
| 800 × 2000 mm | 8 mm | 32kg |
| 900 × 2000 mm | 8 mm | 36kg |
| 1000 × 2000 mm | 8 mm | 40kg |
| 1000 × 2000 mm | 10 mm | 50kg |
| 1200 × 2100 mm | 10 mm | 63kg |
A large shower enclosure can therefore be quite heavy. Make sure you have sturdy fittings, good wall mounting and sufficient help with installation. Want to know more? Read custom shower enclosure: what to look out for or view shower and bath.
Weight of glass table tops
With table tops, the weight is important for the base. A large glass top is often much heavier than expected.
| Table top dimensions | Thickness | Weight |
|---|---|---|
| 1000 × 1000 mm | 6 mm | 15kg |
| 1200 × 800 mm | 8 mm | 19.2kg |
| 1600 × 900 mm | 10 mm | 36kg |
| 2000 × 1000 mm | 12 mm | 60kg |
| 2400 × 1000 mm | 15 mm | 90kg |
Always check whether the base is stable enough and use rubber buffers between the glass and the base. More tips in custom glass table top.
Weight of balustrade glass
Balustrade glass is often laminated or tempered-laminated glass and can therefore become heavy. A balustrade pane of 1000 × 1000 mm with 88.2 glass (together 16 mm) weighs 16 × 2,5 = 40 kg per m². A pane of 1200 × 1100 mm is 1.32 m²:
1,32 × 16 × 2,5 = 52,8 kg
With balustrades, not only the glass must be strong enough, but also the mounting, surface and construction.
What to pay attention to when installing
Glass weight and mounting
The heavier the glass, the more important good preparation. For heavy windows, please note:
- Lifting aids and glass vacuum cleaners
- Number of persons
- Transport, stairwells and passageways
- Load-bearing capacity of frame or base
- Suitable fittings
- Safe workspace and edge protection
- Personal safety
Glass edges and corners are vulnerable. Never place glass firmly on stone, concrete or metal — always use soft underlays.
Glass weight and hinges
Weight is extra important for glass doors, shower doors and revolving windows. Hinges and fittings have a maximum load capacity. Always check:
- Weight of the glass plate
- Maximum load on the hinge
- Number of hinges
- Glass thickness and glass width
- Mounting surface and direction of rotation
A door may fit in size, but still be too heavy for the chosen fitting.
Glass weight and frames
When replacing single glazing with HR++ or triple glazing, the window often becomes heavier. This can cause problems, especially with rotating windows. NB:
- Hinges and locks
- Frame weight
- Wood rot and subsidence
- Glazing beads and rebate depth
- Carrying blocks
Fixed windows can often carry more weight than rotating parts. With old window frames you must check extra carefully whether the new glass is technically suitable.
Common mistakes with glass weight
- Count the cavity as glass weight — with HR++ and triple glazing you only count the glass plates, not the air or gas space.
- Underestimate weight — a glass plate of 1000 × 2000 mm in 10 mm already weighs about 50 kg.
- Do not check fittings — hinges, clamps and profiles have a maximum load.
- Do not check base — a glass table top may be too heavy for a light base.
- Do not take lifting into account — large glass plates are difficult to grip; glass suckers are often necessary.
- Put glass on hard surface — corners and edges may be damaged or broken; always use soft underlays.
Checklist: calculate glass weight before ordering
- What are the width and height in meters?
- What is the glass thickness in millimeters?
- Is it single glass, tempered glass or laminated glass?
- For insulating glass: what is the thickness of all glass plates together?
- How much does the window weigh approximately?
- Can the frame, fittings or base support this?
- Can you lift the glass safely?
- Are glass vacuum cleaners needed?
- Does the glass fit through doors, stairs and corridors?
- Is extra help required with installation?
- Is the surface strong enough?
- Are soft support points or buffers necessary?
Conclusion
Glass weighs on average approximately 2.5 kg per square meter per millimeter of glass thickness. This allows you to quickly calculate how heavy a glass plate will be using the formula breedte (m) × hoogte (m) × glasdikte (mm) × 2,5 = gewicht (kg). With HR++ and triple glazing you only count the glass panes, not the cavity: a HR++ pane of 4-15-5 therefore weighs as if it were 9 mm glass, not 24 mm.
Always calculate the weight before ordering glass. This way you know whether the frame, fittings, base and installation are suitable. This prevents dangerous or expensive mistakes, especially with shower walls, table tops, glass doors and balustrades.
Read more: which glass thickness do you choose, tempered or laminated glass and measure glass correctly. Ready to order? Go to custom glass and immediately calculate the price for your size.