Concrete Mix Ratios: The Complete Guide

What are Concrete Grades?

Concrete grades denote the compressive strength of the concrete after 28 days of curing. The "M" stands for Mix, and the number (e.g., 20) represents strength in MPa (Megapascals).

Standard Mix Ratios

• M10 (1:3:6): used for leveling courses and non-structural work.
• M15 (1:2:4): used for foundations and pavements.
• M20 (1:1.5:3): Standard for general construction slabs and beams.
• M25 (1:1:2): High strength for heavy loads and water retaining structures.

Calculating the exact volume of dry materials is tricky because dry volume is about 54% higher than wet volume. Our Concrete Calculator handles this "Dry Volume Factor" (1.54) automatically.