Work out concrete mix design (m20) instantly with clear inputs, formula shown and shareable results.
M20 nominal mix is 1 part cement to 1.5 parts fine aggregate to 3 parts coarse aggregate by volume. Converting the dry volume split into mass uses bulk densities of 1440 kg/m³ for cement, 1600 for sand and 1450 for 20 mm aggregate, and water follows from the chosen water-cement ratio applied to the cement mass.
Material masses
Cement kg = dry volume / 5.5 x 1440; sand and aggregate follow their parts and bulk densities
Water
Litres = cement kg x water-cement ratio
Preliminary estimate only. Structural concrete requires a designed mix, trial batches and cube testing to the applicable standard.
Cement kg = dry volume / 5.5 x 1440; sand and aggregate follow their parts and bulk densities. M20 nominal mix is 1 part cement to 1.5 parts fine aggregate to 3 parts coarse aggregate by volume.
Only for small or non-critical elements. Codes require design mixes with trial batches and cube testing for structural concrete above modest grades.
This calculator takes 3 inputs: Concrete volume, Water-cement ratio, Dry volume factor. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.