Concrete mix ratios (cement : sand : aggregate) by grade, with material quantities per cubic metre. Nominal mixes up to M20, design mixes above M20 per IS 10262.
Select Concrete Grade
M5 M7.5 M10 M15 M20 M25 M30 M35 M40 M45 M50 M55 M60
Mix Ratio: 1 : 1.5 : 3
fck: 20 MPa · Use: RCC — minimum for structural use · Min Exposure: Moderate
All Grades — Quantities per m³
Grade Ratio Cement Sand Agg Water w/c M5 1 : 5 : 10 2.5 0.44 0.88 120 0.6 M7.5 1 : 4 : 8 3.1 0.44 0.88 140 0.6 M10 1 : 3 : 6 4.2 0.44 0.88 155 0.6 M15 1 : 2 : 4 6.3 0.44 0.88 175 0.55 M20 1 : 1.5 : 3 8 0.42 0.84 180 0.5 M25 1 : 1 : 2 10.8 0.38 0.76 180 0.5 M30 Design Mix 10 0.46 0.68 165 0.45 M35 Design Mix 10.5 0.44 0.66 160 0.45 M40 Design Mix 11 0.42 0.64 155 0.4 M45 Design Mix 11.5 0.4 0.62 150 0.4 M50 Design Mix 12 0.38 0.6 150 0.35 M55 Design Mix 12.5 0.36 0.58 145 0.35 M60 Design Mix 13 0.34 0.56 140 0.32
Exposure vs Minimum Grade (IS 456 Table 5)
Exposure Min Grade Max w/c Min Cement Examples Mild M20 0.55 300 kg Concrete fully protected, interiors Moderate M25 0.5 300 kg Sheltered from rain, not in contact with ground Severe M30 0.45 320 kg Exposed to rain, alternate wetting/drying Very Severe M35 0.45 340 kg Coastal areas, aggressive ground Extreme M40 0.4 360 kg Tidal zone, direct sea water, chemicals
Thumb Rules
• 1 bag cement = 50 kg = 0.035 m³
• Dry volume = 1.52 × wet volume (compaction factor)
• For nominal mixes up to M20, no design mix is required per IS 456
• Design mix mandatory for M25 and above
• Maximum w/c ratio governs durability, not strength alone
• Add 10% extra for wastage in site batching
• Slump: 25–50mm (mass concrete), 50–100mm (RCC), 75–150mm (pumped)
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