Difference Between Mass And Weight

Difference Between Mass And Weight- I know that you guys are finding about the difference between mass and weight, okay before describing about the difference between mass and weight let me discuss the basic concept and definitions of mass and weight.

What Is Mass?

Mass is best defined as the fundamental property of any matter. Mass has its own S.I unit i.e. kilogram.  Mass can also be defined scientifically. It is as follows that mass is a measure of an object’s resistance to acceleration when a force is applied. This is said to be an inertial measure of resistance. So larger the mass more is the resistance towards acceleration acted upon by the same force. There also exists different kinds of mass in science. When mass is the measure of gravitational flux i.e. surface integral of gravitational field by an enclosed surface. Science even says that energy can also be measured by mass. This is possible by Energy-mass relation.

Now comes the quantum mass which is given by the difference between an object’s quantum frequency and its wave number. That’s enough regarding the definition of mass relying on various fields. You can move on to the definition of weight. So that you can have brief difference between mass and weight.

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What Is Weight?

Weight is often confused with mass. But weight is said to be the product of mass and earth’s gravity. So something must have struck in your mind. Gravity is not the same everywhere. It differs from planet to planet and even in moon. So, weight can distinguish from one place to another. Even on earth gravity differs in equator and the poles by a difference of 0.2 m/s. so weight of an object will not be similar with the weight of the same object at equator. On the other hand, mass is constant everywhere. So, it can be said that the combination of mass and gravity gives rise to weight.

Now let’s move on to the common confusion. The difference between mass and weight.

Difference Between The Mass And The Weight

As far it is described above you must be clear with the definitions of mass and weight. So, the difference between the mass stuff and weight is mass is a constant whether weight is not constant. We often come across mass and weight confusion. Weight is very different from mass as it varies from place to place.  Mass is a constant it does not depend on any conditions. But weight depends upon a gravitational field. Conceptually mass refers to an intrinsic property of an object, whereas weight measures an object’s resistance to deviating from its natural course of free fall. We know that according to Newton’s second law force is the product of mass and acceleration. We also know that gravity due to acceleration is used by weight for its existence. So, weight can also be referred as a force.

In case of no gravity situation, there would be a condition of weightlessness. These things give a good difference between mass and weight. Although weight consists of mass in its formula it is not similar to mass. Weight is proportional to mass and acceleration due to gravity in all situations. It must be accelerated by a force. For conditions like when objects are subjected to mechanical accelerations from forces other than resistance of a planetary surface, the weight force is proportional to the mass of an object multiplied by the total acceleration away from freefall, called as proper acceleration.

This in total gives well defined a statement. When a body falls freely the weight is said to be zero whereas the mass of the body remains constant as before. Even in units, there is a good difference between mass and weight. For mass the S.I unit is kilogram. But kilogram meter upon second square is the S.I unit given to weight by the international system of fundamental units.

Let us understand the difference between mass and weight with a suitable example. Suppose you are considering a body of mass 25 Kg. then the weight of the body is said to be 250 Kg approximately. But this not the end the weight varies accordingly. We know that acceleration due to gravity at equator is 9.8 m/s2. So, the weight for a body of 25Kg is given by 245 Kg which is 5 Kg less then the weight of the same body at poles. Similarly, the weight of the same body on moon is said to be 40.5 Kg. this is because the acceleration due to gravity is given as 1.62 m/s2. So, this might have sorted the confusion regarding mass and weight.

The difference between mass and weight should be clarified to students. The above example will clearly make students understand the key differences for mass versus weight. There are different instruments for the measure of mass and weight. Some of them are spring balance, digital weighing machines etc.

In quantum mechanics when it comes to theory of relativity and Einstein stuff, the mass has been differently defined. There come two types of mass i.e. rest mass and another is relativistic mass. Rest mass is also known as Newtonian mass and it is a kind of invariant mass.

On the other hand relativistic mass is given as the total energy of the system divided by the square of the speed of light. Relativistic mass varies with velocity. It gets increased with an increase in velocity. This is the simple difference between rest mass and relativistic mass. but there also exists a relation between them. The rest mass and the relativistic mass is related by an equation.

The equation is given by

Relativistic mass= rest mass * Lorentz factor.

Lorentz factor is represented by the symbol of lambda.

You must have also known about the Law of conversation of mass. It states that mass can neither be created nor be destroyed. In simple words mass remains constant. This statement holds the same when it comes to rest mass.

Both rest mass and relativistic mass can be incorporated with energy mass equations. Relativistic mass is not in use nowadays. Because relativistic mass is directly proportional to the energy so it can vary. This is all about rest mass and relativistic mas provided as short note.

We all are quite familiar with kilograms, pounds, grams, etc. but the confusion still remains between mass and weight. Difference between weight and mass has been neatly described from scientific sources.

For more information comment on the comment section. Find out the confusion for different things. ask us to provide you the best difference between doubts by mailing or commenting. Hope with the above information the confusion regarding difference between mass and weight should be cleared.

Short 3 notes to have clear vision on the difference between mass and weight.


  • Mass is a constant.
  • It gives the same measure wherever it is measured.
  • The S.I unit of mass is Kg. Mass is an intrinsic and a fundamental property.


  • Weight is not constant at all places.
  • The S.I. unit of weight is KG*M/S^2.
  • Weight is directly proportional to the gravity’s acceleration.

Anurag Yadav

Hello, Viewers My Self Anurag Yadav And I Am Founder Of This Blog [ TrickyTech.org ] Which Is Related To Tech.