Concrete Mix Ratio Calculator

Work out concrete mix ratio instantly with clear inputs, formula shown and shareable results.

About Concrete Mix Ratio Calculator

Dry ingredients bulk down when mixed with water, so the dry volume is taken as 1.54 times the wet concrete volume. That dry total is then split by the mix ratio, and cement volume is converted to bags using a bulk density of 1440 kg/m³.

Formulas

Dry volume

dry volume = wet volume × 1.54

Ingredient split

ingredient = dry volume × part / (sum of parts)

Worked example

With the default values below, Concrete Mix Ratio Calculator returns Cement volume of 0.220000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total wet concrete volumeminimum 0 m³: 1 m³
Cement partsminimum 0: 1
Sand partsminimum 0: 2
Aggregate partsminimum 0: 4

Results

Cement volume: 0.220000 m³
Sand volume: 0.440000 m³
Aggregate volume: 0.880000 m³
50 kg cement bags: 6.336

Step by step

1Values used
2Dry volume
3Ingredient split
4Cement volume= 0.220000 m³
5Sand volume= 0.440000 m³
6Aggregate volume= 0.880000 m³
750 kg cement bags= 6.336

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 6 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

One cubic metre of 1 : 2 : 4?

Dry volume 1.54 m³ split seven ways gives 0.22 m³ cement, 0.44 m³ sand and 0.88 m³ aggregate, about 6.34 bags of 50 kg cement.

Why 1.54 and not 1?

Voids between the dry particles fill with cement paste and water during mixing, so more dry material is needed than the finished volume suggests.