The "M" stands for mix and the number is the characteristic compressive strength in N/mm² (MPa) that the concrete must reach at 28 days. M20 concrete must reach 20 N/mm², M25 must reach 25 N/mm², and so on.
Typical uses by grade
| Grade | Strength at 28 days | Typical use |
|---|---|---|
| M10 | 10 N/mm² | PCC levelling course, bedding under footings |
| M15 | 15 N/mm² | PCC flooring, non-structural work |
| M20 | 20 N/mm² | RCC slabs, beams, columns and footings in houses (mild exposure) |
| M25 | 25 N/mm² | RCC in moderate exposure, multi-storey buildings |
| M30 | 30 N/mm² | Severe exposure, heavier structures, commercial buildings |
| M35–M40 | 35–40 N/mm² | Very severe exposure, high-load and special structures |
Minimum grade required by IS 456
IS 456 sets the minimum grade for reinforced concrete according to how exposed the structure is:
- Mild exposure — M20
- Moderate exposure — M25
- Severe exposure — M30
- Very severe exposure — M35
- Extreme exposure — M40
Why ready mix instead of site mixing?
- Batched by weight in a plant — consistent strength in every load.
- Faster pours for slabs, with less labour on site.
- Less wastage and no storage of cement, sand and aggregate on site.
Always follow your structural engineer
The grade shown on your structural drawings is the one to order. If you are unsure, share the drawing with us and we will confirm the right mix before delivery.