Stone carpet calculator
Quick answer: For 10 m² of stone carpet 10 mm thick at a 1:15 ratio you need about 158 kg of stone (7 × 25 kg bags) and about 11 kg of binder with 5% extra.
Natural stone and PU binder for a stone carpet by area, layer thickness and ratio
How the calculation works
Enter the area, choose the layer thickness, the binder-to-stone ratio and the reserve. The calculator works out the weight of natural stone, the number of 25 kg bags, and the polyurethane (PU) binder, rounded up to packs of 20, 5 and 1 kg.
Formula and assumptions
Stone (kg) = area × 15 kg/m² per cm × thickness (cm) × (1 + reserve ÷ 100). Bags = stone ÷ 25, rounded up. Binder (kg) = stone ÷ N for a 1:N ratio. The binder is rounded up to whole kilograms and combined from 20, 5 and 1 kg packs; when only 1 kg is missing to a larger pack, the larger pack is used.
Worked example
Area 10 m², layer 10 mm, ratio 1:15, no reserve: stone = 10 × 15 × 1 = 150 kg = 6 bags of 25 kg. Binder = 150 ÷ 15 = 10 kg = 2 × 5 kg. With a 5 % reserve: stone 157.5 kg → 7 bags; binder 10.5 kg → 11 kg = 2 × 5 kg + 1 × 1 kg.
More worked examples
- Area 20 m², layer 8 mm, ratio 1:15, reserve 5 %: stone 20 × 15 × 0.8 = 240 kg; with reserve 252 kg → 11 bags of 25 kg. Binder 252 ÷ 15 = 16.8 → 17 kg (for example 3 × 5 kg + 2 × 1 kg).
- Area 6 m², layer 12 mm, ratio 1:10, no reserve: stone 6 × 15 × 1.2 = 108 kg → 5 bags of 25 kg. Binder 108 ÷ 10 = 10.8 → 11 kg = 2 × 5 kg + 1 × 1 kg.
Layer of 10 mm, ratio 1:15, no reserve
| Area (m²) | Stone (kg) | Bags of 25 kg | Binder (kg) |
|---|---|---|---|
| 5 | 75 | 3 | 5 |
| 10 | 150 | 6 | 10 |
| 20 | 300 | 12 | 20 |
| 30 | 450 | 18 | 30 |
| 50 | 750 | 30 | 50 |
What affects real consumption
- Layer thickness: every extra millimetre adds 1.5 kg of stone per m².
- Ratio: 1:10 uses more binder than 1:20.
- Edges, stairs, an uneven substrate and grain size change the real consumption.
Common mistakes
- Forgetting that the thickness multiplies the stone: every extra millimetre adds 1.5 kg per m².
- Mixing up the ratio; 1:10 uses more binder than 1:20 for the same amount of stone.
- Ignoring edges, steps and uneven substrate, which raise real consumption.
Frequently asked questions
Is 15 kg of stone per m² per cm exact for every stone?
It is the calculator's working norm; actual consumption depends on grain size and how the mix is laid, so check the manufacturer's data sheet.
Does the calculator work out the price?
No, it only calculates the quantities of stone and binder; the price depends on the supplier and the product.
How much stone do I need for 30 m² at 10 mm?
30 × 15 × 1 = 450 kg of stone, which is 18 bags of 25 kg, and 450 ÷ 15 = 30 kg of binder at 1:15.
How does the ratio change the binder amount?
For 150 kg of stone, 1:10 needs 15 kg of binder, 1:15 needs 10 kg and 1:20 needs 7.5 kg, which the calculator rounds to 8 kg.
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Publisher: Art-Visum d.o.o. · Content reviewed:
Calculations use common consumption rates and manufacturers' technical data sheets; results are estimates. Methodology · Standards · About