Mass vs Weight: What is Mass & Weight? Difference, Unit, How to Calculate?

Do you know the difference between mass vs weight? A physical body’s mass is the total amount of matter it contains. Solids, liquids, gases, and plasmas are the four basic forms of matter. In addition to taking up space by taking up a volume, matter is defined as anything with at least one mass. The Earth attracts everything towards its center, no matter its state. Also, just as life is attracted to the Earth, its center is also attracted to celestial objects.

A force is always attracted to like there are different celestial objects which are attracted by different forces. It is also true that the attraction force varies with a celestial object’s distance from the center. The force responsible for attracting material towards the Earth’s center is called weight. As a result, mass and weight are two different things in the true sense of the word. 

Why People Confuse about in Mass vs Weight?

You can easily do this when you are not entirely certain how science defines them exactly. Even though they are related, there is a fundamental difference between them. In physics, mass is a measure of how much matter is in an object and weight is a measure of how much force gravity exerts on an object.

Mass vs weight what difference unit how calculate
Mass vs weight what difference unit how calculate Image:

You’re aware of your weight and have spent hours agonizing over how much muscle you built during your last gym visit as you are conscious of your weight every day. 

Mass and weight are two words that we frequently interchange in our day-to-day lives. Most people consider these two words to be equivalent, considering them to be alternatives to one another. It should be noted, however, that technically these two quantities are different. There is an important difference between mass and weight is that mass specifies how much matter is contained within a body. In contrast to weight, gravity refers specifically to the pull of the earth’s gravity on a body with a certain mass.

Define Mass & Weight

What is Mass?

A mass can be measured by counting the number of protons, neutrons, and electrons in an object. It is basically the amount of stuff in an object that determines its mass. Obviously, this partial definition isn’t complete, but for now it’s enough. The kilogram and the gram are the most common units of mass. You can use the mass unit if you insist on using silly imperial units.

Mass will be calculated as weight multiply by gravity. You could weigh 1 kilogram of steel and 1 kilogram of feathers and they would both weigh the same. It’s just their volume that would be different. Due to their light weight, feathers would require a much larger volume than steel. For the same mass, more atoms are needed, which means more space is required. It is denoted as ‘m’

What is Weight?

Objects with mass interact gravitationally. The weight of an object is the force it exerts on the Earth when it interacts with it. Weighing is measured in Newton, just like other forces, and pounding is another measurement. It is denoted as ‘W’ and its value is mass x gravitational effect, i.e., W = m x g

Define Unit of Mass & Unit of Weight

Unit of Mass

Mass is measured in a variety of units, including kilograms, grams, lbs, pounds, etc., but the SI unit is kilograms. It is possible to convert any unit of mass to another unit by using a conversion formula without affecting its mass.

Unit of Weight

As weight is represented as W = mg, from here the unit of weight can be easily understood. Unit of weight = unit of mass x unit of gravitational effect. In S.I unit, the unit of weight = kg x m/s2 or Newton. Do you know what does unit weight mean? Unit weight is defined as weight (W) per unit volume (V) of a material with uniformly distributed mass m, typically represented by the Greek letter gamma. At any randomly chosen point within the material, density is defined as mass divided by volume, and represents the density of the entire sample very accurately.

Key Functions of Mass and Weight

Key Functions of Mass

By removing some of an object’s parts, you can change its mass. The mass of your backpack decreases when you remove books from it at the end of the day. It can also increase when you add more matter. A child’s body grows bigger and stronger as they grow.

Due to the process of converting food energy into matter for their body, the child’s mass will increase. Understanding that mass does not change with changes to its shape, location or size is essential. 

No matter how high you stretch or how curled up you are on the couch, your body has the same mass. There is no difference whether you are at home, at the beach, or at school. 

After you eat breakfast, your mass is a little bit higher than when you wake up in the morning. Objects are measured by their mass, which is a fundamental measure of matter.

In this regard, it is noteworthy that the mass of the body remains constant regardless of how particles are arranged throughout the body. This means that the mass of a body does not change when its location changes or when gravity is applied by the earth. Therefore, there is no difference in mass between the earth and the moon, regardless of where the object is located.

Key Functions of Weight

Body Weight of a Person

A person’s body weight is, however, the ideal definition of body weight. The gravitational force acting on a body will cause an individual’s weight to differ. It is important to note that in physics, weight is measured in Newton.

The most common way to measure weight is in kilograms(Kg). It is also common that in some countries, such as the United States, pounds are used in place of kilograms, since weight is determined by kilograms, while mass is determined by pounds.

A person’s weight is usually measured while wearing clothes, but not while wearing any other objects. Wallets, shoes, mobile phones, etc. are included here. People often use their weight as an indicator of their health and well-being.

Space Program

The relationship between mass and weight is illustrated by rocket launches. Fuel-filled rockets have a greater mass at launch. At Earth’s surface, gravity also exerts its greatest force. The weight of the Earth is therefore the greatest. Several minutes after launch, most of the rocket’s fuel was burned. As a result, the rocket has lost mass due to the energy it was transformed into. In addition, the rocket is farther from ground level than it was before.

Therefore, gravity pulls less forcefully on it then their masses as well as its weight have decreased. Now the rocket’s engines can launch the rocket even faster than when it was launched. 

Varies in Location

Hence, weight details how much force an object with a certain mass receives when it is attracted to the surface of the earth. Weight changes with location because gravity is involved in the case of weight. The difference in weight between an earthly body and a lunar body is due to this reason. A variation can also be seen with higher and lower altitudes.

What are the Different Types of Mass?

Mass is usually expressed in kilograms, abbreviated as kg. Atomic mass is measured in terms of the number of atoms and molecules, which is denoted with U, the atomic mass unit. The mass of a carbon-12 atom is equal to one atomic mass unit.

Different methods are used to determine mass in physics. Inertial mass and gravitational mass are two of the most common types of mass.

Gravitational Mass

Measured in gravity mass, an object is determined by how much it exerts on other objects. Objects can also be measured by the amount of gravity they experience from another object.

Inertial Mass

A person’s inertial mass is determined by how much resistance he or she has to acceleration. If two objects are pushed together under the same conditions and with the same force, the object with a lower mass will accelerate faster.

Difference between Inertial Mass & Gravitational Mass

Physically, gravitational mass and inertial mass do not differ from each other. Several experiments have been conducted to check the values, and they always agree within the margin of error for the experiment.

The fact that gravitational and inertial mass were equal led Einstein to postulate that gravitational mass is equal to inertial mass in his Theory of General Relativity.  Much like pennies spiralling around a hole in a common donation toy at your favorite chain store, gravity occurs when there is a valley or slope in the space-time continuum.

Gravitational Mass: The gravitational mass of an unknown mass is determined by comparing its force of gravity to that of a known mass. Typically, balance scales are used for this purpose. Because of the same gravitational acceleration on each object, the masses will balance out no matter where you are or on what planet you are on.

Due to the high gradient of the gravitational field around super massive objects such as black holes and neutron stars, this does break down.

Inertial Mass: A mass’s inertial mass can be determined by applying a force to an unknown mass, measuring the acceleration, and applying Newton’s Second Law. As accurate as the accuracy of your measurements, this is the mass value.  Astronauts usually find their inertial mass when they want to weigh in outer space.

Mass vs Weight: What is the Difference?

01. Measurement difference between Mass vs Weight

The weight of an object is determined by a scale that measures the pull of gravity on that object. By balancing a body’s mass with another known amount of mass, one can measure its mass. The mass of an object can be measured with a pan balance, while the weight of an object can be measured with a spring balance. In the case of constant gravity, for example on Earth, methods could be interchanged.

02. Gravity Effect

The weight of an object depends on the gravity at that place while Mass is always a constant at any place and any time. An object’s mass is 60 kg, then its Weight would be 600 Newton but when taken to the Moon, this object will have a weight of 100 Newton as the gravity of the moon is one sixth that of the Earth. But the mass of that object will remain the same.

03. External Force

The mass of an object is an intrinsic characteristic and is not affected by external factors. As opposed to this, weight is determined by both its mass attracting it, as well as its force of attraction.

04. Units

Due to the fact that mass has nothing to do with direction, it is a scalar quantity. There is a force acting downward here, so weight is a vector quantity.  While mass is measured in grams or kilograms, weight is measured in Newton.

05. Location

Regardless of where a body is located, its mass remains constant.  But the weight of a body gives you a variety of locations.

06. Quantity

Weight is known as a derived quantity, while mass is considered an independent quantity.

07. Mass vs Weight: Scalar or Vector?

We all know that scalar quantity means it has only magnitude and no direction. On the other hand vector quantity means it has magnitude and direction both. Now, mass has only magnitude, so it is scalar quantity and weight has both magnitude and direction, so weight is vector quantity.

08. Mass vs Weight: Can it be Zero?

As mass is an independent property of material, it can not be zero, whether, weight is dependent on gravitational effects, so where net gravity is zero, weight can be zero.

Mass vs Weight: Difference in Table

The amount of stuff in an object The force it exerts on the Earth when it interacts with it
Independent of locationDependent of location
Independent of gravitational effectDependent of gravitational effect
Mass can never be zero of a matterWeight can be zero of a matter, if there is no gravitational effect
Scalar quantity as it has only magnitudeVector quantity as it has both magnitude and direction
Normally measured in kg, and gramsNormally, measured in Newtons
Mass is denoted as ‘m’Weight is denoted as ‘W’ = mg
Measured using a pan or ordinary balanceMeasured by spring balance
Can not be affected by wind can be affected by wind load
Mass vs Weight Difference

Weight & Mass Proportional to each other

Mass changes then something’s weight changes also. Whenever, something’s gravitational force changes, its weight also changes. It is rare for the mass of something to change, but it can change in many different ways in terms of weight. 

Your exact feeling of gravity depends on the density of the planet. Our planet Earth has a gravitational force which is measured in G.

There are less gravity on the moon than there are on Earth because of its size and density. The moon has a gravity of 1/6 that of Earth. It’s not very dense, even though Jupiter is bigger and more massive than Earth. Jupiter has 2.5 times Earth’s gravity.

Relation between Mass & Weight: How to Calculate?

Newton 2nd Law

Mass can be regarded as the constant of proportionality between the object’s acceleration and the force acting on it. 

F proportional to mass which is written as F=ma.

F represents force applied; m represents mass, and a represents acceleration.

Newton’s second law of motion defines mass this way.

An object’s mass is also affected by the gravitational force it produces. Gravitational mass refers to this mass.

Unsupported objects accelerate toward Earth, which indicates that Earth produces gravitational forces, but it is not obvious that objects in general produce gravitational forces.

Objects such as humans, or even much more massive objects such as large buildings, are unable to clearly observe the gravitational forces produced by Earth due to its greater mass.

Law of Conversation of Mass

A closed system’s mass must remain constant over time according to the law of conservation of mass. The mass of a system must still remain constant despite changes being made to the objects within it.

Relation between Mass & Gravity at various Distance

Gravitational pull between you and the body you are standing on is measured by your weight. There are a few factors that determine gravity’s force. You are affected by the mass of the planet on which you stand as well as your mass. Gravity pulls twice as hard on you if you double your mass.

Gravity pulls twice as hard on you if the planet you are standing on is twice as massive. Alternatively, distance from the planet’s center reduces its pull on your body, whereas closer to it is stronger. Within a short time, the force starts to weaken. You will experience one-fourth of a planet’s force if you double it’s distance from you. One-ninth of the force is lost when you triple the separation. It happens because air gets caught under the parachute and pushes back up against gravity’s pulling power. As the parachute falls, it is actually slowed down by the air.

Physics Experiment to distinguish Mass & Weight

Feather & Ball Test without Vacuum

Test Process

  • While standing up, hold your hands out in front of you with the backs of your hands facing up. After that, you hold the ball in one hand and the feather or tissue in the other.
  • Watch the objects fall as you open both hands simultaneously. It is possible to determine which one reaches the ground first.
  • Hold your hand flat under the paper and drop the ball and a sheet of paper by pulling your hand out to let it fall. The speed at which they reach the floor can be evaluated.
  • You form a ball out of one sheet of paper. At the same time, you can drop the entire sheet of paper and the paper ball. 
  • Watch what happens when you drop the ball and the paper ball simultaneously.

Test Results

The ball hit the ground much sooner than the feather, even though both were dropped from the same height.  The ball probably also reached the ground before the sheet of paper. 

There was probably a delay between the paper ball hitting the floor and the paper sheet hitting it. There was no difference in weight between the two pieces of paper, so why did one reach the floor first & other is not.

You can try it again, but you will find that the ball always reaches the ground before the sheet of paper. You might have been even more surprised by the results of the test process. As soon as the regular ball reached the ground, the paper ball did too. 

Falling speed of any object is determined by its mass or weight. The ball has more mass, so it should fall first. Understanding why objects fall is essential to understanding this. Falling objects are caused by gravity. Gravity pulls down on a ball thrown into the air or kicked into the air.

No matter how heavy an object is, gravity pulls on it equally, so they all fall at the same speed.

That explains the paper ball and the regular ball landing simultaneously. Well, objects will fall at the same speed if no other force is acting on them. They both started out falling at the same pace, but as soon as the air pushed up against them, they began to fall at a faster rate. As a ball is round and smooth, the air couldn’t resist it very much, and gravity still overpowered the air’s push against it.

Paper, tissue & feathers are affected by the air resistance due to the air beneath the objects pushed against them, thus slowing their descent. An object’s shape directly affects its air resistance. Let’s imagine an object falling with a parachute.

Feather & Ball Test in Vacuum

It simulates the conditions of outer space by placing spacecraft in a giant vacuum chamber. We would finally be able to see how gravity affects objects without any interference once all the air is removed from the room.

Dropping both heavy and light objects at the same time in this test is designed to determine which will hit the ground first. It is not happened every time that heavier objects fall to the ground first.

It turns out that they will all fall at the exact same pace. However, air resistance makes some objects fall slower, such as feathers. It is necessary to remove all the air in the room in order to see how gravity affects feathers.

The result is undeniable because high-speed cameras capture every fraction of a second. A vacuum is created in the chamber, and the bowling ball and feathers are released, falling gracefully to the ground. At the exact same time, both objects crash into the wooden crate below as they descend more than 30 feet.

Despite being the foundation of Albert Einstein’s theory of relativity, the findings of Galileo and Newton’s original experiments led to the theory of gravitation.

Theory of Relativity

Newton’s theory of gravitation was quickly accepted without question and remained unquestioned until the dawn of the twenty-first century. In 1905 and 1915 Albert Einstein introduced his Special Theory of Relativity and General Theory of Relativity, shaking the foundations of physics.

The first showed that Newton’s Three Laws of Motion were only approximately correct when velocities approached that of light. Another study found Newton’s Law of Gravitation to be only approximately accurate, because it broke down in the presence of very strong gravitational fields.

This is Einstein’s most famous theory, and it has very significant implications. A person going very fast relative to Earth will measure the seconds ticking by more slowly than someone on Earth if the speed of light is always the same. For the astronaut, time is slowed down, a phenomenon called time dilation.

Difference in uses for Mass & Weight

Weight Measuring in Rubber Bands

Hanging objects from rubber bands allows you to compare their weights. Rubber bands are stretched further by gravity on Earth when they are heavier than lighter objects. Test your predictions by suspending heavy and light objects from rubber bands.

Checking Mass in Car

Experiments that move horizontally rather than vertically are the easiest way to study mass on Earth. Because gravity can’t change an object’s position, objects can’t move. Build a Mass Car and accelerate the mass across rollers or a low-friction track via an air pump. 

Test the hypothesis by changing the mass of the car and seeing how it changes how far it rolls. In order to graph the distance the car travels against its mass, you need to know how much it weighs. Utilize the international space station experiment to predict if the results will differ in space.

Measuring Tape in mass Acceleration

If you do not have access to an air pump or mass car, you can use a retractable tape measure to accelerate an object. Remove one meter or three feet of measuring tape from an object. Press the button to retract the tape measure after securing it or holding it. 

Weight Measure in Elevator

If you are standing on a scale in an elevator that is accelerating upward, you will feel heavier than when the elevator is stopping, because the elevator’s floor presses harder on your feet. As a result, the scale will read higher than when the elevator is silent. In contrast, when the elevator accelerates downward, you are lighter. A scale’s apparent weight is the force it exerts; it does not change with constant speed. There are three situations in the elevator which is mentioned below:

  1. You feel heavier as the elevator accelerates upward as gravity pulls you in the wrong direction & your weight will be higher.
  2. Your weight is similar when the elevator is at rest.
  3. As the elevator accelerates downward, you and the elevator are in free fall, since there is no weight exerts & no force on you.

Define Body Mass Index

A body mass index can also be used to assist with this. Based on a person’s weight and height, this index measures relative weight. Calculated by dividing a person’s body mass in kilograms by their height in meters squared, BMI is a weight-for-height ratio. 

Based on a person’s height and weight, the BMI determines whether they are overweight, underweight or normal weight. Nevertheless, the BMI has been criticized, particularly regarding where to define overweight and obesity. Additionally, the BMI has been perceived to have numerous limitations.

Define Modern Theory of Gravitation

The General Theory of Relativity is the best current theory of gravitation. Relativity theory and Newton’s theory differ in their predictions only when velocities and gravitational fields are larger than what is experienced on Earth. Newton’s three laws and his theory of gravitation are generally adequate under most conditions. In our discussion of cosmology, we will return to this issue.

This helps you understand how gravity is determining any object’s weight not mass. Mass will always be the same regardless of the position of the object. But weight will vary due to the gravity.

Define Gravitational Field

Gravitational fields are produced by the mass of the Earth. Gravitational fields are regions within which gravitational forces act on objects. A mass comparable to the enormous mass of Earth is required to produce a gravitational force sufficiently strong to accelerate objects at a rate visible to human senses.

There is a gravitational field due to the mass of any object; but for objects on Earth, its gravitational field produces forces that are approximately zero. Earth is the only object that produces a gravitational field for most examples when considering objects on Earth.


We have therefore clarified that mass and weight are two interrelated but distinct quantities. On the basis that mass is simply the quantity describing how much matter is present in it, this statement is accurate. The force that attracts mass to the earth is defined by its weight.

Most people use these terms interchangeably, but that only works since we are all here on Earth. It will be harder to talk about how much stuff we have if we move to space colonies, the moon, or other planets. Taking weight versus mass into account, here’s the breakdown. A physical body’s mass indicates how much matter is inside it, whereas its weight shows how the body is attracted to the Earth.


How body mass change in planet to planet?

There is no effect of gravity or the presence of other planet entities upon the mass of anybody on a planet because its mass is constant on every planet. Physique is intrinsic to the body, and it does not change in response to the environment. Nevertheless, a body’s weight will change when gravity’s acceleration changes.

Can mass be zero when the weight is zero?

A person is considered weightless when there is no downward force acting on the body. Furthermore, it means that a body is not subjected to constant gravitational pull caused by a planet, but it still retains mass. This property will remain constant until the body ceases to exist because mass is intrinsic to the body.

Is size same as mass?

Size and volume are not the same thing as mass. It is due to the atoms’ or molecules’ composition and density that determine the mass of the molecule. The mass of a balloon filled with helium will be much lower than that of a solid gold item of similar size.

Can Mass or Weight of an object be zero?

Since matter is the only component of a body, mass can never be zero. In the absence of gravity, however, the weight of a body can be 0 due to the product of mass and gravity.


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