Work out exactly how much concrete — and cement, sand and stone — your slab needs.
Ordering the right concrete volume avoids waste and shortfalls. Here is the simple method plus material quantities.
| Step | Basis | Result |
|---|---|---|
| Volume | L × W × thickness | m³ |
| Cement (25 MPa) | per m³ | ~7 bags |
| Add waste | safety | +10% |
Why builders choose us
- Volume = L×W×thickness
- ~7 cement bags/m³
- Add 10% waste
- Match sand & stone
Related pages
Frequently asked questions
How do I calculate concrete for a slab?
Multiply length × width × thickness (all in metres) for m³, then order ~7 cement bags plus sand and stone per m³, adding 10% for waste.
How thick should a slab be?
About 85–100mm for a house surface bed; 100–125mm for driveways.