Cement Calculator
Calculate how many kilos of cement and how many bags you need based on the volume to fill and the recommended dosage for your type of mortar or concrete.
How is it calculated?
Cement needed (kg) = volume (m³) × dosage (kg of cement per m³). Bags needed = kg of cement ÷ bag size, rounded up. 300 kg/m³ is a common dosage for general use, but check your cement's spec sheet for the exact dosage for your application.
Examples
2 m³ with 300 kg/m³ dosage and 25 kg bags
You need 600 kg of cement: 24 bags of 25 kg.
0.5 m³ with 350 kg/m³ dosage and 25 kg bags
You need 175 kg of cement: 7 bags of 25 kg.
Rough cement dosage guide
These are rough values: follow your cement's spec sheet and a professional's guidance for structural work. If you don't know the volume yet, calculate it with the concrete calculator.
| Use | Kg of cement per m³ |
|---|---|
| Bonding mortar | 250–300 |
| General-use concrete | 300 |
| Structural concrete | 300–400 |
From dosage in kg/m³ to bags
Common cement bags are 25 kg or 50 kg: divide the total kg by the bag size and round up, because an opened bag that isn't fully used hardens with moisture and can't be saved for another job. If the volume you're filling is a full slab, also try the concrete calculator, built for that case with premixed bags.