How to calculate Volume of concrete for Slabs, Columns, Beams, Retaining wall & Footings

In this article, you are going to learn

How to calculate the volume of concrete for Slabs, Beams, Columns, Footings & structural members of the building.

If you wanted to skip the basics and know about how to calculate for the specific component you can click on below links

The procedure for calculating the quantities of cement, sand, aggregate & water is already discussed. If you are not aware of the procedure read here. 

In order to calculate quantities of cement, sand, aggregate & water required for any concrete volume. Firstly, we have to work out the volume of concrete and then, quantities of individual ingredients are computed.   

Let’s begin with the basics.

Definition of Volume:-

Volume is an amount of space that occupies. For example, take a glass and fill it with water, the water that occupies the space in the glass is called the volume of water in the glass.

Same for concrete, take a box of length (1m), breadth,(1m) depth(1m) and fill it with concrete.

The Volume of concrete for below box= Length x Breadth x Depth=  1m x 1m x 1m =1m³

To fill 1m³ of box, 25KN of concrete is required. [1KN = 100Kgs]. 

Density of Concrete = 25KN/m³

Volume is the calculation of 3dimensional, which means the three dimensions are multiplied.

The basic definition of the volume = multiplication of the three dimensions = L x B x D

The formula changes as per shape, but methodology remains the same to calculate the volume of any shape i.e., the three dimensions should be multiplied. Take an example of the cylinder which doesn’t have length and breadth. To calculate the volume of a cylinder, the area of the circle is calculated and then it is multiplied by the height of the cylinder. (refer below mentioned circular column for cylinder example)

To avoid confusion, consider the below-mentioned formula for concrete volume calculation.

Calculation of Volume of concrete for Slabs:

A slab is in the shape of a rectangle, In order to calculate the volume of concrete required for the slab, find out the surface area of the slab and then multiply it with the depth/thickness of slab as shown in fig.

From the above fig Length = 6m, Breadth = 5m and thickness/depth of the slab = 0.15m

The volume of Concrete = Area of rectangle x Depth

Area of Rectangle = Length x Breadth
The Volume of concrete = Length x Breadth x Depth = 6x5x0.15=4.5m³
Hence, 4.5m³of concrete is required to build an above slab.

Remember, all values should be computed in m.

Calculation of volume of concrete for the column:

The column may be in any shape, either it may be in rectangular or circular or hexagonal etc.

The volume of concrete = Surface Area x Depth

Rectangular column:

From the above fig, Length = 0.6m, Breadth=0.4m, Height of column = 3m

Calculating the top surface area and multiplying it with the depth or height of the column.

Volume of Concrete = 0.6×0.4×3= 0.72m³

Circular column:

From below fig, the radius of circle = 0.25m.

The volume of concrete for circular column = Surface Area of Circle x height of the column.

Volume of Circular column = πr² x 3 = 3.14 x 0.25² x3 = 0.58m³

Calculation of volume of concrete for beams:-

Beams are generally in a rectangular shape, to calculate the volume of concrete required for beams calculate the top or bottom surface area of the beam and multiply with the depth of beams.  

Volume of concrete for rectangular beam = Surface area x Depth = length x width x depth = 4×0.5×0.4=0.8m³

Calculation of volume of concrete required for footings:-

To make ease in understanding I am considering the Plain footing.

For calculation purpose, I am dividing the footing into two parts.

Part1: It is in a rectangular shape with the following dimensions length=1.0m, breadth=0.8m and depth=0.4

The volume of 2nd part = 1.0mx0.8×0.4 = 0.32m³

Part 2:-

Volume of concrete = 1.2x1x0.1 = 0.12m³
Total volume of concrete required for footing= 0.32+0.12=0.44m³

Calculation of Volume of concrete required for Retaining Wall:

The calculation part of the retaining wall is similar to slab volume calculation,

From the above fig, Volume of concrete for retaining wall = Surface area x Depth

= 10×3.5×0.1 =3.5m³

Automatic calculator to calculate individual ingredients of concrete (Cement, Sand, Aggregate & water):-

How to use the calculator:-

• In the first field of below form,  enter the required amount of concrete in m³
• To get the individual quantities of ingredients to specify the ratio of cement, sand and aggregate. To know the ratio of different grades of concrete refer here.
• Make sure that each and every value you are entering in the below form is in “m” or “metre”. For other units Use google conversion tools to convert into m.
• For finding the quantity of water,  Enter the Water/cement ratio as per requirement. It usually ranges from 0.35-0.50

Related Articles:

• Important Properties of concrete.
• How to calculate the quantity of cement mortar  required for Plastering
• Curing of concrete.