Concrete calculator
The element fills, then the mix breaks down into cement bags, piles of sand and gravel, and litres of water.
The drawing
- Cement bags 21
- Sand 1.2 m³
- Gravel 2.4 m³
- Water 525 L
What you need
| Material | Calculated need | To buy | Unit price | Total |
|---|---|---|---|---|
| CPJ 42.5 cement (50 kg bags)CPJ 42.5 cement — 50 kg bag | 1 050 kg | 21 bagsexactly what you need | ||
| River sand 0/4Washed river sand 0/4 — m³ | 1.2 m³ | 1.5 m³0.3 m³ left over | ||
| Gravel 8/15Gravel 8/15 — m³ | 2.4 m³ | 2.5 m³0.1 m³ left over | ||
| Mixing water | 525 L | not sold | — | — |
| Indicative total | ||||
Working out prices…
The formula
3 m³ × 350 kg/m³ = 1050 kg of cement; 3 m³ × 400 L of sand and 800 L of gravel; water ≈ 175 L/m³.
The assumptions
- 350 kg/m³ mix, dry aggregates, no admixture.
- Sand and gravel are rounded up to the delivered half m³.
- Dimensions and reinforcement are those set by your engineer.
- A qualified engineer or architect must design and approve every structural element — slabs, beams, columns, foundations, reinforcement and load-bearing walls. Our calculations give indicative quantities and budgets, never dimensions.
How to use it
Choose the element: slab, footing, column or beam.
Enter the dimensions and the count your engineer set.
Read the volume and the mix at the chosen dosage, in 50 kg bags and delivered m³.
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