🏗️ Cement Calculator

When cement, sand, and aggregate are mixed with water, the dry materials compact and fill air voids, resulting in a volume roughly 35–54% less than the sum of the dry volumes. To get the correct wet concrete volume, multiply the wet volume by 1.54 to determine the required dry material volume. This is the industry-standard dry volume factor.

For M15 mix (1:2:4): approximately 6.3 bags per m³. For M20 (1:1.5:3): approximately 8.1 bags per m³. For M25 (1:1:2): approximately 10.8 bags per m³. Higher grade concrete requires more cement per cubic metre.

A water-cement (W/C) ratio of 0.45–0.55 is typical for structural concrete. Lower W/C ratios produce stronger, more durable concrete but are harder to work with. This calculator uses a W/C ratio of 0.5 as the standard. Never add extra water on site — it weakens the mix.

Cement is the binding agent (typically Portland cement) that, when mixed with water, creates a paste that hardens. Concrete is the final product made by mixing cement, sand (fine aggregate), coarse aggregate (gravel), and water. Cement makes up only about 10–15% of a concrete mix by volume.