Concrete Grade Reference Guide

Common Concrete Mix Ratios and Typical Compressive Strengths

Grade Mix Ratio (Cement : Sand : Aggregate) Typical Strength (28 Days)
M5 1 : 5 : 10 5 MPa (725 psi)
M7.5 1 : 4 : 8 7.5 MPa (1,090 psi)
M10 1 : 3 : 6 10 MPa (1,450 psi)
M15 1 : 2 : 4 15 MPa (2,175 psi)
M20 1 : 1.5 : 3 20 MPa (2,900 psi)
M25 1 : 1 : 2 25 MPa (3,625 psi)
M30 1 : 0.75 : 1.5 30 MPa (4,350 psi)
M35 1 : 0.65 : 1.3 35 MPa (5,075 psi)
M40 1 : 0.6 : 1.2 40 MPa (5,800 psi)
Note: Mix ratios for M5–M20 are traditional nominal mixes. M25 and above are generally produced using design mixes, and the ratios shown here are approximate values commonly used for preliminary estimating and educational purposes.

Steel Reinforcement Reference

Thumb-rule estimates per ft³ of concrete — based on steel density 7,850 kg/m³

Structure Type Steel % Weight per ft³ (kg) Weight per ft³ (lb)
Footing 0.67% 1.50 kg 3.31 lb
Residential Slab 1.00% 2.22 kg 4.89 lb
Beam / Column 2.00% 4.45 kg 9.81 lb
Heavy Structural 3.00% 6.67 kg 14.71 lb
Note: These are thumb-rule estimates for preliminary budgeting only. Actual steel quantities must be determined by a structural engineer based on design loads, spans, and applicable building codes.