Difference Between Mass and Weight

Difference between mass and weight is one of the most frequently asked questions. Some students often use the terms mass and weight interchangeably, which is completely wrong. It is important to know what they are and how they are related. 

Mass

• Mass is simply the measure of the amount of matter in a body.
• Mass is denoted by “M”.
• Mass is always constant for a body and there are several formulas to calculate mass.
• One way to calculate mass is: Mass = volume × density
• Mass is a base quantity.
• Mass only has magnitude and so, it is a scalar quantity.
• The SI unit of mass is Kilogram (Kg).
• Mass does not depend upon gravity and is constant everywhere.
• Mass can never be zero.
• Mass can be easily measured using any ordinary balance like beam balance, lever balance, pan balance, etc.

Weight

• Weight is the measure of the amount of force acting on a mass due to acceleration due to gravity.
• Weight is denoted by “W”.
• Weight is the measure of the gravitational force acting on a body.
• Weight can be calculated from the following formula: Weight = mass × acceleration due to gravity
• Weight is a derived quantity.
• Weight has both magnitude and direction (towards the centre of gravity) and so, it is a vector quantity.
• The SI unit of weight is Newton (N).
• Weight is dependent on gravity and so, it varies from place to place.
• Weight can be zero where there is no gravity (like space).
• Weight can be measured by a spring balance or by using its formula.