Quantity Calculation of Concrete

Calculation of concrete or quantity calculation of concrete is the most common thing in the construction projects. In this article, we will discuss the "calculation of concrete". It is possible to calculate quantities of concrete materials such as cement, sand, and aggregates for the production of the required quantity of concrete of the given mix proportions such as 1:2:4 (M15), 1:1.5:3 (M20), 1:1:2 (M25) using the absolute volume method.
The principle behind this method is that the volume of fully compacted concrete is equal to the absolute volume of all concrete materials, i.e. cement, sand, coarse aggregates, and water.

Based on the type of construction, a concrete structure can consist of beams, slabs, columns, and bases, etc. The amount of concrete required for concrete structure can be determined by summing up the volumes of each structural component or member's sections.

The volume can be measured as length x width x height (or depth or thickness) of a rectangular cross-sectional member. An appropriate equation should be used for different members ' cross-sectional shapes.

The formula for calculating materials for the necessary concrete volume is given by;

calculation of concrete | quantity calculation of concrete

Where, Vc = Absolute volume of fully compacted fresh concrete

W =Mass of water

C = Mass of cement

Fa = Mass of fine aggregates

Ca = Mass of coarse aggregates


Sc, Sfa, and Sca are the specific gravities of cement, fine aggregates, and coarse aggregates respectively.

The air content has been ignored in this calculation.


This method of calculation for quantities of materials for concrete takes into account the mix proportions from design mix or nominal mixes for structural strength and durability requirements.

Now we will learn the material calculation by an example.

Calculating Quantities of Materials for per cubic meter or cubic feet or cubic yards concrete.

Consider concrete with a mix proportion of 1:1.5:3 where, 1 is part of cement, 1.5 is part of fine aggregates and 3 is part of coarse aggregates of the maximum size of 20mm. The water-cement ratio required for the mixing of concrete is taken as 0.45.

Assuming bulk densities of materials per cubic meter, cubic feet and cubic yards as follows;

Cement = 1500 kg/m3 = 93.642 lb/ft3 = 2528.332 lb/cubic yards

Sand = 1700 kg/m3 = 105 lb/ft3 = 2865.443 lb/cubic yards

Coarse aggregates = 1650 kg/m3 = 103 lb/ft3 = 2781.166 lb/cubic yards

Specific gravities of concrete materials are as follows;

Cement = 3.15

Sand = 2.6

Coarse aggregates = 2.6.

The percentage of entrained air assumed is 2%.

The mix proportion of 1:1.5:3 by dry volume of materials can be expressed in terms of masses as;

Cement = 1 x 1500 = 1500

Sand = 1.5 x 1700 = 2550

Coarse aggregate = 3 x 1650 = 4950.

Therefore, the ratio of masses of these materials w.r.t. cement will as follows =

calculation of concrete | quantity calculation of concrete

= 1 : 1.7 : 3.3

The water cement ratio = 0.45

Now we will calculate the volume of concrete that can be produced with one bag of cement (i.e. 50 kg cement) for the mass proportions of concrete materials.


Thus, the absolute volume of concrete for 50 kg of cement =

calculation of concrete | quantity calculation of concrete

Thus, for the proportion of mix considered, with one bag of cement of 50 kg, 0.1345 m3of concrete can be produced.



We have considered an entrained air of 2%. Thus the actual volume of concrete for 1 cubic meter of compacted concrete construction will be = 1 -
0.02 = 0.98 m3.


Thus, the quantity of cement required for 1 cubic meter of concrete = 0.98/0.1345 = 7.29 bags of cement.

The quantities of materials for 1 m3 of concrete production can be calculated as follows:

The weight of cement required = 7.29 x 50 = 364.5 kg.

Weight of fine aggregate (sand) = 1.5 x 364.5 = 546.75 kg.

Weight of coarse aggregate = 3 x 364.5 = 1093.5 kg.