Calcvers
Cement Calculator
Bulk Materials
Generated
September 24, 2026
Cement bags (25 kg)
19 bags
12 m² slab · General (1:2:4)
Your inputs
- Currency
- USD ($)
- Length
- 4 m
- Width
- 3 m
- Thickness / depth
- 10 cm
- Mix strength
- General (1:2:4)
- Waste / overage
- 10 %
Breakdown
- Or 50 kg bags
- 10
- Cement needed
- 463 kg
- Mix
- General (1:2:4)
Cement share of the mix
| Item | Value |
|---|---|
| Cement | 463 kg |
| Aggregate | 1453 kg |
What this means
Cement is one part of the concrete mix — with sand, aggregate and water. The amount of cement per cubic metre depends on the mix strength: a lean mix uses about 300 kg of cement per m³, a general 1:2:4 mix about 350 kg, and a strong mix about 420 kg. After computing your slab's volume and adding waste, we convert that to the number of standard bags. Stronger mixes make harder concrete, but they also cost more and are harder to work.
Recommendations
- For footings, foundations and structural slabs, use a strong mix and follow your structural drawings.
- Match the mortar mix to the brick type — soft old bricks need a weaker (leaner) mortar.
- Buy bags from the same brand and check the best-before date; old cement is noticeably weaker.
Watch out
- These are typical figures — bag sizes and yields vary by region and brand.
- Water ratio is critical; too much water weakens concrete more than a weak mix does.