Cement Calculator

How it works

1. 1Enter your total wet concrete volume in cubic metres or cubic yards.
2. 2Select your mix ratio (1:2:4 general, 1:1.5:3 structural, 1:3:6 lean) and the cement bag size.
3. 3The calculator applies a 1.54 dry/wet factor, takes the cement portion, and divides by bag weight — rounding up to whole bags.

Use cases

• Estimating cement bags for a house foundation or floor slab before placing a supplier order.
• Comparing mix ratios to understand the cost and strength trade-off between mixes.
• Quick site checks when a batch-plant quote needs verification against hand-mixed quantities.

Frequently asked questions

Why is a 1.54 dry/wet factor used?

Dry aggregates contain air voids that collapse when wetted and compacted. Multiplying the wet volume by 1.54 accounts for this bulking, so the dry ingredients add up correctly. 1 m³ of wet concrete needs about 1.54 m³ of dry mix.

How is cement mass found from volume?

The cement share of the dry volume is multiplied by the bulk density of cement, about 1440 kg/m³. For a 1:2:4 mix and 1 m³ pour: 1.54 × (1/7) ≈ 0.22 m³ → ≈ 317 kg → 7 bags of 50 kg.

Should I order extra cement for waste?

Yes. Site losses from spillage, edge over-pour, and mixer residue typically add 5–10%. For critical pours, confirm with your contractor and check local building-code mix requirements.