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.
• And how to use an automatic calculator to find quantities of individual constituents of concrete (Cement, Sand, Aggregate & Water)

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

If you are here for automatic calculator click here or to calculate the volume of concrete for different structural members follow me:-

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.   

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 as 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 = 1000Kgs]. 

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 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.

Formulae for Calculating Volume of Concrete:-

The Volume of concrete= Surface Area x Depth

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

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=4.5m3Hence, 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.

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, radius of circle = 0.25m.

Volume of concrete for circular column = Surface Area of Circle x height of 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 rectangular shape, to calculate the volume of concrete required for beams calculate the top or bottom surface area of 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 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