Work out cement sand aggregate quantity instantly with clear inputs, formula shown and shareable results.
Dry materials occupy more space than the concrete they produce because water fills the voids, so wet volume is multiplied by about 1.54 to get dry volume. That dry volume is then split by the nominal mix parts. Cement volume is converted to bags using a bulk density of 1440 kg/m³ and 50 kg per bag.
Dry volume
Dry = wet volume x 1.54
Material split
Each material = dry volume x its part / sum of parts; cement bags = cement m³ x 1440 / 50
Dry = wet volume x 1.54. Dry materials occupy more space than the concrete they produce because water fills the voids, so wet volume is multiplied by about 1.54 to get dry volume.
The factor covers bulking of sand and the voids in the aggregate, both of which vary with grading and moisture. Anything between 1.52 and 1.57 is defensible; 1.54 is the common site value.
This calculator takes 3 inputs: Wet concrete volume, Nominal mix, Dry volume factor. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.