Concrete Mix Ratio Calculator — Nominal Mix Reference

A ratio like 1:2:4 represents cement:sand:aggregate by volume. For every 1 part cement, use 2 parts sand and 4 parts coarse aggregate. This is called a "nominal mix" — a standard proportion not based on lab testing of specific materials, suitable for general construction up to M20 grade.

Nominal mix (like 1:2:4 for M20) uses fixed standard proportions regardless of the specific cement/aggregate being used — simpler but less precise. Design mix calculates exact proportions based on lab testing of your actual materials (cement strength, aggregate size, water quality) to achieve a target strength most economically. Design mix is mandatory for M25 and above per IS 456.

M10: 1:3:6, M15: 1:2:4, M20: 1:1.5:3, M25: 1:1:2 (nominal, though M25 typically requires design mix per code). Higher grades (M30+) require lab-designed mixes and cannot be reliably achieved with nominal ratios.