Cement Calculator
Estimate the cement bags, sand, and aggregate needed for a concrete mix. Free online cement calculator for slabs and footings.
Dry Volume = Wet Volume × 1.54
2.832 m³ × 1.54 = 4.361 m³
17.8 bags
Cement (50 kg bags)
Sand Volume
1.246 m³
Aggregate Volume
2.492 m³
Total Dry Volume
4.361 m³
Cement Volume
0.623 m³
Sand Volume
1.246 m³
Aggregate Volume
2.492 m³
How Does the Cement Calculator Work?
Enter the volume of concrete you need and select a mix ratio. The calculator converts wet volume to dry volume using a factor of 1.54 (accounting for shrinkage and voids), then divides the dry volume into cement, sand, and aggregate portions based on the chosen ratio. One bag of cement is taken as 50 kg, which occupies approximately 0.035 m³.
Example
For 100 cubic feet of concrete at a 1:2:4 mix: Wet volume is 2.832 m³, dry volume becomes 2.832 × 1.54 = 4.361 m³. Cement portion: (1/7) × 4.361 = 0.623 m³, which equals 0.623 / 0.035 = 17.8 bags. Sand: (2/7) × 4.361 = 1.246 m³. Aggregate: (4/7) × 4.361 = 2.492 m³.
Common Use Cases
- Estimating material quantities for house construction in India.
- Planning concrete pours for foundations, slabs, and columns.
- Budgeting material costs before ordering from suppliers.
- Quick on-site verification for small to medium construction jobs.
FAQs
Why is the dry volume factor 1.54?
When cement, sand, and aggregate are mixed dry, there are voids between particles. The dry volume is typically 52–54% more than the wet volume. A factor of 1.54 is the standard assumption used in Indian construction practice.
What does the mix ratio 1:2:4 mean?
The ratio represents the proportion of cement : sand : aggregate by volume. A 1:2:4 mix (often called M15 grade) is suitable for general reinforced cement concrete work such as floors and footings.
How many kilograms does one bag of cement weigh?
In India, one bag of cement is standardised at 50 kg. The volume of one bag is approximately 0.035 m³ (35 litres) when loosely packed.