Concrete Mix Calculator

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Cement bags, sand and aggregate in m³ and cft for a concrete volume at 1:1.5:3, 1:2:4, 1:3:6 or your own ratio — with water

This tool runs entirely in your browser — no file or data is sent to any server.

Enter the values

What to work out

Mix ratio (cement : sand : aggregate)

Wet (finished) concrete volume

Dry volume factor

A common textbook allowance is 1.54

Cement bulk density

kg/m³

Cement per bag

Water–cement ratio (optional; 0 to skip)

Result

Cement (bags)

6.34

Sand

15.538cft

Aggregate

31.077cft

Bags come whole — round up. Add your own site allowance for wastage if you need one.

This is the nominal-mix (volume ratio) method. For a design mix, take the quantities from the mix design itself.

Working

Formulas

Assumptions

The dry volume factor 1.54 is a common textbook allowance (for voids and the bulking of sand); some books use 1.52 — change it if yours does.
With cement bulk density 1440 kg/m³ and a 50 kg bag, one bag = 50 ÷ 1440 = 0.0347 m³ (about 1.225 cft) — both can be changed.
The water–cement ratio 0.5 is only an example input; enter the value from your specification or mix design. 1 kg of water is taken as 1 litre.

Sources: B. N. Dutta, Estimating and Costing in Civil Engineering; S. C. Rangwala, Estimating and Costing · B. C. Punmia, Building Construction

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