Calculate the exact volume of concrete needed for any project — slabs, columns, beams, footings, and stairs. Shows cubic metres, cubic feet, number of bags, and estimated cost.
Multiply length × width × thickness. For a 5m × 4m slab at 150mm (0.15m) thick: 5 × 4 × 0.15 = 3 cubic metres. Always add 10% for wastage.
For M20 grade concrete (1:1.5:3 mix), 1 cubic metre requires approximately 8 bags of 50kg cement, 630 kg of sand, and 1,260 kg of 20mm aggregate.
Multiply wet concrete volume by 1.54 to get dry material volume. This accounts for voids and compaction — dry materials take up more space than mixed concrete.
1 cubic metre = 35.315 cubic feet. For example, 3 m³ = 3 × 35.315 = 105.94 cubic feet.
M20 concrete has a compressive strength of 20 N/mm². It uses a 1:1.5:3 ratio of cement:sand:aggregate and is the standard grade for residential slabs, beams, and columns.
Add 5–10% for machine-mixed concrete and 10–15% for site-mixed concrete. This calculator uses 10% by default — adjust for complex shapes or site conditions.
A standard transit mixer holds 6–8 cubic metres. In India, a small transit mixer holds 4–6 m³. Always check with your supplier before ordering.