grade of concrete

What Is Grade of Concrete & Its Ratio for Mix

What Is the Grade of Concrete?

Grades of concrete are defined by the concrete mix proportion and the minimum strength of concrete at end of 28 day curing period.

The Concrete Grade is can be known by calculating the compressive strength of concrete in Mpa, where M stands for mix and the MPa denotes the overall strength

There are different types of concrete mix that are based on concrete classification according to its compressive strength.

For making concrete we use cement, sand, aggregate, and water which are mixed with a certain ratio, and concrete is cast and put in a cube of 150 mm size and put in a water bath for 28 days and afterward, it is tested in a compression testing machine. The compressive stress result is known as the “grade of concrete”. It is expressed in N/mm²

The concrete grade is denoted by M10, M20, M30, and so on according to their compressive strength.

Read More: Concrete Mix Design Step By Step Full Calculation

Concrete Grade As Per Indian Standards

Grade of Concrete
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The “M” refers to Mix and Number after M (M10, M20) Indicating the compressive strength of concrete after 28 days of curing and testing.

M indicates the proportion of materials like Cement: Sand: Aggregate (1:2:4) or Cement: Fine Aggregate: Coarse Aggregate.

If we mention M10 concrete, it means that the concrete has 10 N/mm2 characteristic compressive strength at 28 days.

In the designation of concrete mix M  to the mix and the number to the specified compressive strength of 150 mm size cube at 28 days, expressed in N/mm^2.

Read More: How To Check Compressive Strength Of Concrete

Concrete Grade Per British/European standards

As per  BS 8500-2 British/European standards, the grade of concrete is denoted as C10, C15, C20, C25, etc., ‘C’ which means ‘Concrete Strength class’, and the number behind C refers to characteristic Compressive strength of Concrete in N/mm2 @ 28 days when tested with the 15 cm dia. & 30 cm height cylinder in a direct compression test.

Concrete Grade
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The grade of concrete is also denoted as C16/20, C20/25, C25/30, etc., which means Concrete Strength Class (C) the number behind C refers to the Compressive strength of Concrete in N/mm2 when tested with Cylinder / Cube.

Different mix proportions of the materials used to make concrete namely

  • Cement
  • Coarse aggregate
  • Fine aggregate
  • Water

Resulting in concretes with different properties.

Concrete Classification

Following are the Standard Concrete Grade with their Mix Proportions and Strength

Grades of  Concrete Mix Ratio (Cement: Sand: Aggregates) Compressive Strength
MPa (N/mm2)
Lower Grade of Concrete
M5 1: 5:105 MPa725 psi
M7.51: 4: 87.5 MPa1087 psi
M101 : 3: 610 MPa1450 psi
M151: 2: 415 MPa2175 psi
M201: 1.5 : 320 MPa2900 psi
Standard Grade of Concrete
M251: 1 : 225 MPa3625 psi
M30Design Mix30 MPa4350 psi
M35Design Mix35 MPa5075 psi
M40Design Mix40 MPa5800 psi
M45Design Mix45 MPa6525 psi
High Strength Grade of Concrete
M50Design Mix50 MPa7250 psi
M55Design Mix55 MPa7975 psi
M60Design Mix60 MPa8700 psi
M65Design Mix65 MPa9425 psi
M70Design Mix70 MPa10150 psi

The Selection of the Grade of Concrete Depends on the Situation and Uses

Concrete Grade (N/mm2)Ratio  Cement, Sand, and AggregatesUsage
201:1.5:3Normal Construction Concrete
251:1:2Reinforced concrete/precast
30Concrete Mix DesignHeavy Reinforced concrete/pre-cast
35Concrete Mix DesignPre-stressed/pre-cast concrete
40Concrete Mix DesignVery heavy reinforced concrete/pre-cast/prestressed
45Concrete Mix DesignVery heavy reinforced concrete/pre-cast/prestressed


In conclusion reinforced cement concrete is a widely used construction material which combines the strength of concrete and the tensile strength of steel reinforcement, RCC is essential for building bridges, building dams, and foundations.

By utilizing mix proportions, sound construction practices, RCC structure can be constructed to be robust and long lasting..

In conclusion the grade of concrete refers to the quality of the concrete and strength of the concrete mixture used in construction projects, also the concrete grade is denoted by a numerical value such as M7.5, M10, M20, M30 and so on and the letter “M” is stand for mix and the number represent its compressive strength of concrete in unit (MPa).

It is essential to determine the appropriate grade of concrete and to ensure that the structure can withstand the environmental conditions and anticipated loads.

The ratio for the mix concrete plays a crucial role in determining the its grade of concrete, the mix ratio is representing the proportion of different ingredients which is used in the concrete mixture such as cement, fine aggregate, coarse aggregate, sand, water and admixture.

The mix ratio is expressed the weight or volume of each ingredient relative to the total volume or weight of mixture.

The choice of mix ratio is depending on various factors such as desired strength of the concrete, availability of material, nature of work.

Watch Video: What is the Grade of Concrete and Different Types used in Construction


What is the grade of concrete?

The grade of concrete refers to the strength and quality of concrete that is specified for a particular construction project. It indicates the compressive strength of the concrete that it can achieve after a specified curing period.

What factors determine the appropriate grade of concrete for a project?

Several factors influence the selection of the appropriate grade of concrete for a project, including the structural requirements, expected loads, environmental conditions, and the specific application of the concrete. These factors are typically determined by structural engineers and other professionals involved in the project.

Can the ratio for the mix of concrete be adjusted based on project requirements?

Yes, the ratio for the mix of concrete can be adjusted based on specific project requirements. Concrete mix designs are customized to meet the structural and performance requirements of a project. Engineers and concrete technologists analyze the project needs and conduct tests to determine the suitable mix ratios.

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