How much does a square metre of granite weigh?
Weight is the most underestimated item in stone purchasing: it drives freight, drives container loading, and decides whether the floor slab can take it. The calculation is one multiplication — but thickness and units must be right.
One formula: volume times density
Granite density is about 2700 kg/m³. Weight per square metre equals 2700 times thickness in metres. For 30mm that is 0.03, so 2700 times 0.03 gives 81 kg. Remember that one line and you can size any thickness yourself, without being misled by roughly twenty or thirty kilos.
What do the common thicknesses weigh?
Converted at 2700 kg/m³ below. The same table works in reverse: take the container's payload limit, divide by the unit weight, and you know the maximum area it can carry.
| Thickness | Weight per m² | Weight per 100 m² |
|---|---|---|
| 20mm | 54 kg | 5.4 t |
| 25mm | 67.5 kg | 6.75 t |
| 30mm | 81 kg | 8.1 t |
| 40mm | 108 kg | 10.8 t |
| 50mm | 135 kg | 13.5 t |
Why is the real weight a little higher?
Three reasons: thickness tolerance, since a nominal 30mm cut at 32mm is about six percent more material; packing, because pallets, crates and separators all weigh something; and moisture. So leave margin when planning a container — never push the theoretical figure to the payload limit. How much margin is covered in the loading article.
Which costs does this number touch?
Three: ocean freight, charged on weight or volume whichever is greater; inland transport and lifting; and structural design. The first two are money, the third is safety. Facade cladding and large countertops depend on the third most — an extra 13.5 kg per square metre over several thousand square metres is tens of tonnes.
How do square metres convert to square feet?
One square metre is about 10.764 square feet. If a supplier quotes per square foot, divide the per-square-metre weight by 10.764: 30mm works out at roughly 7.5 kg per square foot. When units differ, convert to one before comparing prices.