Enter your sizes
Assumptions (change if your office uses different constants)
Result
Nominal mixes as traditionally used; IS 456:2000 allows nominal mix concrete only up to M20.
How it’s calculated
Questions
How many cement bags are needed for 1 m³ of M20 concrete?
For a nominal 1:1.5:3 mix, about 8 bags (≈ 400 kg) of cement per m³, with about 0.42 m³ of sand and 0.84 m³ of aggregate.
Why multiply by 1.54?
Dry materials shrink when mixed with water as the voids fill up, so about 54% more dry volume is needed for 1 m³ of wet concrete. Some offices use 1.52 or 1.57 — change it under Assumptions.
Can I use this for M25 or M30?
No — M25 and above should be produced to a design mix (IS 10262) with proportions by weight from a lab. This calculator is for nominal mixes up to M20, which IS 456 allows.
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