How to Calculate Concrete Volume
Calculating the correct amount of concrete for your project prevents waste and saves money. The formula varies by structure shape.
Slab / Footing Formula
Volume (m³) = Length × Width × Thickness
All dimensions must be in meters.
Example: A slab 5 m × 4 m × 0.15 m = 3 m³ of concrete.
Circular Column Formula
Volume (m³) = π × (Diameter/2)² × Height
Example: A column with 30 cm diameter and 3 m height = π × 0.15² × 3 = 0.212 m³.
How Many Cement Bags Do I Need?
For standard M20 concrete (1:1.5:3 mix), approximately 1 bag of 50 kg cement covers 0.035 m³ of concrete. So for 3 m³: 3 ÷ 0.035 = 86 bags.
Always add 5–10% extra for wastage and filling voids.
Need cement quantities for a specific mix ratio?
Open Mix Ratio Calculator →Tips for Accurate Estimation
- Always measure twice before ordering concrete.
- Add 10% waste factor for ready-mix deliveries.
- For large pours, consider ordering in multiple smaller loads.
- Check weather — do not pour concrete below 5°C or above 35°C.