Stone Weight Calculator
Mass per square metre and total for stone slabs by density.
Inputs
Result
Formula
| Area | A = length × width in metres |
| Volume | V = A × thickness in metres |
| Mass per piece | V × density × 1000 |
| Mass per m² | thickness (mm) × density |
| Total | per piece × quantity |
| Truck load | area = payload × 1000 ÷ mass per m² |
Fifty 600 × 300 × 20 mm granite pieces: 0.180 m², 0.0036 m³ and 9.72 kg each — 9.000 m² and 486.00 kg in total, about 103 pieces to the tonne.
FAQ
Why do stone deliveries keep overloading?
Because loading by volume badly overshoots on weight. Granite 30 mm is 81 kg/m², so a 30 t truck takes 370 m² of slab; load 400 m² by eye and you are 2.4 t over. Always plan by payload: 370 m² of 30 mm is the ceiling on a 30 t truck.
How does thickness differ between wet-fix and dry-hung?
Wet fixing on cement mortar uses 18-20 mm and relies on full-bed adhesion; dry hanging uses 25-30 mm carried by stainless brackets and framing, with slots or holes cut in the slab. Dry-hung stone under 25 mm cracks at the slot, and wet-fixed stone over 25 mm is heavy enough to debond as the mortar shrinks — wet fixing is barred on tall facades.
How much heavier is granite than marble?
Three to eight percent. Granite runs 2.7-2.8, marble 2.6-2.8, sandstone only 2.2-2.4 and engineered stone 2.3-2.5. At 20 mm that is 54 kg/m² for granite, 53 for marble and 46 for sandstone. Outdoors must be granite — marble weathers badly and acid rain dulls and yellows it.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.