Difference Between Density and Specific Gravity

Even if specific gravity and density, both are used to represent mass, these quantities are quite different from one another. The ratio of mass per unit volume is known as the density of a liquid. On the other hand, specific gravity refers to the relative density of a fluid with respect to another liquid (usually water). 

What Is The Difference Between Density And Specific Gravity?

  • Density – The ratio between mass and volume of a liquid determines the density of a liquid. It is denoted by ρ, and its units can be gm/ cm3, Kg/ m3, Pounds/ cubic inch. 

The formula for density is ρ = m / V, where m is mass and V is the volume of liquid. 

  • Specific gravity – It is the density of a liquid compared to the density of another material for reference. Usually, water is taken as the reference material for this calculation. 

The formula for specific gravity is Specific GravitySubstance = ρsubstance / ρReference

It has no unit and is a dimensionless quantity. 

Further, refer to the table drawn below to know about the difference between density and specific gravity. You will be able to understand different pointers which distinguish between the two terms. 

Difference Between Density and Specific Gravity


Specific Gravity 

The ratio between the mass of the liquid and its unit volume is called density. 

The ratio between the weight of a given substance to the density of an equal volume of water or other reference material is known as specific gravity. 

Volume and weight of a substance must be known for this calculation. 

You must know the density of a substance and density of water for an equal volume for this calculation. 

It is a measure of an absolute term. 

It is a measure of a relative term. 

Unit of density is Kg/ m3

It has no unit. 

The dimensional formula of density is [M L-3]. 

It is a dimensionless quantity.

It has several domestic as well as commercial applications. 

The calculation of specific gravity has applications in industries for the measurement of the solutions concentration. 

Therefore, the main difference between density and specific gravity is the use or application of it. While density measures this mass per unit volume of a liquid, specific gravity is used for measuring relative density. 

Multiple Choice Questions 

  1. Choose the unit for specific gravity. 

  1. N/ m3

  2. Kg/ m3

  3. m/ s2

  4. Dimensionless 

Ans: d 

  1. Calculate the specific gravity of a material whose mass is 10 Kg and volume is 2 cubic metres. Here, the value of reference density is 50 g/ m3

  1. 0.4

  2. 0.1

  3. 0.3

  4. 0.2

Ans: b 

  1. A cone with radius 1m and height of 3m has a specific gravity of 0.1. Calculate the mass of the cone when the density of water is 1000 Kg/ m3

  1. 325.24 Kg

  2. 136.16 Kg

  3. 314.16 Kg

  4. 425.24 Kg

Ans: c 

  1. Why is it essential to mention the temperature of the material at which its specific gravity is computed. 

  1. Density of a material varies with the change in temperature. 

  2. Mass of the material varies with the change in temperature. 

  3. Rigidity of a material varies with the change in temperature. 

  4. None of the above options. 

Ans: a 

While the above discussion on specific gravity vs density concepts is quite detailed, there are quite a few related topics which are also crucial for your Physics curricula. Now you can download our Vedantu app to access detailed study material on all these related topics along with online interactive sessions for better clarity on them.

FAQ (Frequently Asked Questions)

1. What are the specific gravity and density difference?

The main difference between density and specific gravity is its use in measuring this mass of a liquid. Density provides an absolute measure, whereas specific gravity provides a relative measure.

2. What is the density of water?

The density of water is 997 Kg/ m3. It can be utilised in this calculation of specific gravity or relative density. And those materials which are calculated to have a specific gravity below 1, they can float over water.

3. What are the applications of specific gravity?

Specific gravity is calculated for various industry applications. Specific gravity finds its applications in the likes of testing if an amount of gold is real.