Unit of Weight - SI Unit, CGS Unit and Other Units, FAQs

Edited By Vishal kumar | Updated on Jul 02, 2025 05:01 PM IST

In this article, we will talk about the unit of the weight, the SI unit of the weight, the standard unit of weight, cgs unit of weight and the specific weight units.

the SI unit of weight(or the standard unit of weight) is Newton

When we talk about the unit of weight, it sounds confusing. The reason is because weight is measured in terms of force, i.e, Newton whereas the standard unit of mass is Kilograms. We link both weight and mass with each other. However, they are scientifically two different quantities. Similarly, we often get confused about the unit of weight. Now, let’s discuss the difference between weight and mass and also we will discuss the unit of weight and mass.

This Story also Contains

What is the SI unit of weight?
SI Unit of Mass
What is unit weight?(or Specific weight)
Specific weight units
What is the basic unit of weight?
Difference between the SI Units Of Mass and weight.
ALL units of weight

Unit of Weight - SI Unit, CGS Unit and Other Units, FAQs

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What is the SI unit of weight?

SI Unit of weight is Newton(or we can say that the Standard unit of weight is Newton)

We have different weight measurement units but still we study the SI unit of weight because SI units are standard units and are acceptable globally. It is a fixed and uniform way of measuring any physical quantity. Therefore, the SI Unit of weight is Newton or we can say that the Standard unit of weight is Newton. We define newton as “It is the necessary force that is provided to a mass of one kilogram with an acceleration of one metre per square second .”

As we know that the SI unit of weight is Newton. Newton is a derived unit and it can also be expressed in SI base units as kg⋅m/s2

The SI Unit of weight is Newton. We define newton as “It is that force necessary to provide a mass of one kilogram with an acceleration of one metre per second per second.”

Formula of weight : We can calculate the SI unit of weight or the Standard unit weight using the formula given below.

W = F =m g

Where, W = weight[What is the symbol for weight?]

F = Force(net force/external force)

m = mass

g = acceleration of gravity

m = W ÷ g [convert weight to mass]

FORMULA FOR UNIT OF WEIGHT

1 N = 1 kg ms2

Hence, it tells that the SI unit of weight(or the standard unit of weight) i.e, is we require 1N force to move a body of mass 1 kilograms by an acceleration of 1 metre per second square.

The table includes the different weight measurement units such as the SI unit of weight, CGS unit of weight, and the dimension of weight:

SI unit of weight	N
SI base unit of weight	kg.m.s-2
CGS UNIT OF WEIGHT	dyne
DIMENSION OF WEIGHT	MLT-2

CGS Unit of Weight – Dyne. CGS unit implies cm-g-s, where the weight becomes 1 g cm s-2. We can also calculate dyne by dividing 1 N by 10000.

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Other Unit of Weight

Other units of weight known to us are pound-force (lbf), slug, gram, amongst others.

Conversion of The Units Of Weight

1 g = 0.001 kg

1 mg = 1.010-6 kg = 1.010-3 g

1 centigram = 1.010-5 kg = 1.01023 g

1 metric ton = 1.0103 kg[1 unit to ton]

1u=1.6605402E-27 kg[1 unit kg]

SI Unit of Mass

The SI unit of mass is kilograms.[Don’t get confuse it with the SI unit of weight or the standard unit of weight i.e, Newton]

As we know that the standard unit of weight is Newton. But there are many different units systems. Such as the specific weight units and the basic weights.

SI UNIT OF MASS is kg

What is unit weight?(or Specific weight)

The specific weight is also known as the unit weight.

Specific weight is the weight per unit volume of any material.

Also Read:

Specific weight units

We commonly use a value of the unit weight of water. And value on Earth at 4 °C is 9.807 kN per metre cube.It is also known as specific weight for water.

The terms specific weight(or specific density) is also used to measure relative density. Gamma(γ), commonly known as a specific weight symbol.

We define specific weight or the unit weight (γ) of a material as the product of its density ρ and the gravity(standard) g:

γ = ρ g[THE UNIT WEIGHT FORMULA]

Unit of density = kg/m3

cgs unit of density= g/cm^3

gravity(standard)= m/s2

cgs unit of g = cm/s^2

What is the basic unit of weight?

Pounds(lb) is the basic unit of weight.

Difference between the SI Units Of Mass and weight.

The SI unit of mass and weight are as follows:

The SI Unit of mass or the MKS unit of mass is Kilograms & the SI Unit of weight is Newton

(1 N = 1 kg ms2)

cgs units of mass and weight:

cgs unit of mass is grams and cgs unit of weight is dyne.

ALL units of weight

The SI Unit of weight/ standard unit of weight is Newton or we can say that the weight is measured in Newton.
The cgs unit of weight is dyne.
The base unit of weight is kg.m.s-2
The basic unit of weight is pounds(lb)
unit of unit weight is N
Common units of weight are kg, g, mg, etc.

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Hence, we conclude that the standard unit of measuring weight in India and all over the world is Newton(N). The unit of weight in SI system is Newton everywhere. Also, the standard unit for measuring weight is Newton as well.

Also read -

NCERT Physics Notes:

Frequently Asked Questions (FAQs)

1. What’s my weight on Moon?

Weight on the Moon is 16.5% of what we would experience it on Earth. Or we can say, if my weight is 100 kg on Earth, then my weight on moon will be only 16.5 kg .

2. What is the SI unit of weight in Physics?

The SI unit of weight is called Newton.

3. What is the standard unit of weight in Maths?

The standard unit of weight in Maths is also Newton(N).

4. What is the basic unit of weight?

Pounds(lb) is the basic unit of weight.

5. What are the SI and cgs unit of weight?

The SI and cgs unit of weight are Newton(N) & Dyne.

6. What is weight measured in?

weight is measured in Newton.

7. What is the standard unit of measuring weight?

Newton

8. What is the SI unit of mass and weight in terms of physics?

The SI Unit of mass and weight in terms of physics is Kilograms and Newton.

9. Why do we use different units for weight in different systems?

Different unit systems were developed in various regions and for different purposes. The SI system (using Newtons) is internationally standardized, while others like CGS (using dynes) or the imperial system (using pounds) are still used in specific contexts or regions due to historical reasons or practical applications.

10. What is the CGS unit of weight?

In the CGS (centimeter-gram-second) system, the unit of weight is the dyne. One dyne is defined as the force required to accelerate a mass of 1 gram at a rate of 1 centimeter per second squared.

11. How does a Newton compare to a dyne?

One Newton is equal to 100,000 dynes. This large difference is due to the different base units used in the SI and CGS systems. The SI system uses larger base units (meters, kilograms) compared to the CGS system (centimeters, grams).

12. What is the imperial unit of weight?

In the imperial system, weight is typically measured in pounds (lb). One pound is approximately equal to 4.45 Newtons.

13. How does weight change with altitude?

Weight decreases with increasing altitude because the strength of Earth's gravitational field decreases as you move away from the Earth's center. This change is subtle near Earth's surface but becomes more significant at higher altitudes or in space.

14. How is weight different from mass?

Weight is the force exerted on an object due to gravity, while mass is the amount of matter in an object. Mass is constant regardless of location, but weight can change depending on the strength of the gravitational field. Mass is measured in kilograms (kg), while weight is measured in Newtons (N).

15. What is the relationship between weight and mass on Earth?

On Earth, weight (W) is related to mass (m) by the equation W = mg, where g is the acceleration due to gravity (approximately 9.8 m/s² on Earth's surface). This means that an object with a mass of 1 kg will have a weight of about 9.8 N on Earth's surface.

16. Would an object's weight be the same on the Moon as on Earth?

No, an object's weight would be different on the Moon. The Moon's gravitational field is weaker than Earth's, about 1/6 as strong. So, an object would weigh about 1/6 of its Earth weight on the Moon, even though its mass remains the same.

17. Can weight ever be zero?

Yes, weight can be zero in a state of free fall or in the absence of a gravitational field. Astronauts in orbit experience weightlessness because they are in a constant state of free fall around the Earth, even though they are still affected by Earth's gravity.

18. What's the difference between weight and apparent weight?

Weight is the actual force due to gravity, while apparent weight is the force an object seems to exert in certain situations. For example, in an accelerating elevator, your apparent weight may feel greater or less than your actual weight due to the additional forces involved.

19. Why do bathroom scales show kilograms instead of Newtons?

Most bathroom scales are calibrated to show mass in kilograms rather than weight in Newtons for convenience. They assume standard Earth gravity to convert the measured force (weight) into an equivalent mass. This works well on Earth but would be inaccurate in locations with different gravitational strengths.

20. How is weight measured in space?

In space, where objects are often in free fall (weightless), mass is typically measured instead of weight. This is done using devices that measure the inertia of an object, such as the Space Linear Acceleration Mass Measurement Device (SLAMMD) used on the International Space Station.

21. Why don't we just use mass instead of weight in everyday life?

In everyday life on Earth, weight is often more practical because it's what we directly experience and measure (e.g., on scales). Since the gravitational acceleration is nearly constant on Earth's surface, weight is proportional to mass, making it a convenient proxy for mass in most terrestrial situations.

22. Why is weight considered a vector quantity?

Weight is a vector quantity because it has both magnitude and direction. The magnitude is determined by the mass and the strength of the gravitational field, while the direction is always towards the center of the gravitating body (typically downward on Earth's surface).

23. How does weight affect the concept of "weightlessness" in orbit?

Objects in orbit are not actually weightless; they still have weight due to Earth's gravity. However, they experience apparent weightlessness because they are in a constant state of free fall around the Earth. The orbital path curves at the same rate the object falls, creating the sensation of weightlessness.

24. How does the unit of weight relate to pressure?

Pressure is defined as force per unit area. Since weight is a force, it's often used in pressure calculations. For example, the pressure at the bottom of a column of fluid is calculated using the weight of the fluid above it divided by the area.

25. What is the weight of 1 liter of water on Earth?

One liter of water has a mass of approximately 1 kg. On Earth, this translates to a weight of about 9.8 N (Newtons). This relationship (1 liter of water weighing about 9.8 N) is often used as a convenient reference in practical applications.

26. How does the unit of weight relate to energy units?

The unit of weight (Newton) is related to energy units through work. Work is force multiplied by distance, so lifting a weight (applying a force) over a distance produces work, measured in Joules (N·m). This connection is crucial in understanding potential energy in gravitational fields.

27. What's the difference between weight and gravitational force?

Weight is actually the gravitational force acting on an object. The terms are often used interchangeably, but "weight" specifically refers to the gravitational force experienced by an object in a particular gravitational field.

28. How does buoyancy affect measured weight?

Buoyancy reduces the apparent weight of an object immersed in a fluid. The buoyant force is equal to the weight of the fluid displaced by the object, as stated by Archimedes' principle. This is why objects seem lighter or even float in water.

29. What is the SI unit of weight?

The SI unit of weight is the Newton (N). Weight is a force, and in the International System of Units (SI), force is measured in Newtons. One Newton is defined as the force required to accelerate a mass of 1 kilogram at a rate of 1 meter per second squared.

30. How does the unit of weight relate to the concept of impulse?

Impulse is the product of force and time. Since weight is a force, it can contribute to impulse. The unit of impulse is Newton-seconds (N·s), which combines the unit of weight (N) with time. This relationship is important in understanding changes in momentum due to gravitational forces.

31. How does weight affect the concept of terminal velocity?

Terminal velocity is the constant speed achieved by an object falling through a fluid when the drag force equals the gravitational force (weight). Heavier objects generally have higher terminal velocities in the same fluid because the drag force must increase to balance the greater weight.

32. What is meant by "weight fraction" in chemistry and materials science?

Weight fraction is the ratio of the weight of a particular component to the total weight of a mixture or compound. It's often used in chemistry and materials science to describe composition. Unlike mass fraction, weight fraction can vary slightly with location due to changes in gravitational field strength.

33. How does weight relate to the concept of pressure in hydraulic systems?

In hydraulic systems, the weight of the fluid contributes to the pressure within the system. According to Pascal's principle, pressure applied to an enclosed fluid is transmitted equally in all directions. The weight of the fluid itself creates a baseline pressure that increases with depth, which is crucial in designing and operating hydraulic systems.

34. How does the unit of weight relate to power?

Power is the rate of doing work, and work involves force (which can be weight) acting over a distance. The unit of power, the Watt, can be expressed as Newton-meters per second (N·m/s), showing its relationship to the unit of weight. This connection is important in understanding energy transfer rates in gravitational systems.

35. What is specific weight?

Specific weight is the weight per unit volume of a substance. It's calculated by multiplying the density of the substance by the acceleration due to gravity. The SI unit for specific weight is N/m³ (Newtons per cubic meter).

36. What is meant by "weight per unit length" in materials science?

"Weight per unit length" is often used in materials science and engineering to describe linear density. It's typically expressed in units like N/m (Newtons per meter) and is useful for characterizing materials like wires, ropes, or beams where the cross-sectional properties are consistent along the length.

37. How does weight relate to the concept of "g-force"?

G-force is a measure of acceleration relative to freefall. One "g" is equal to the acceleration due to Earth's gravity at sea level (about 9.8 m/s²). When experiencing higher g-forces, objects feel heavier because the apparent weight increases proportionally to the g-force.

38. Can weight be negative?

In physics calculations, weight can be considered negative when it acts in the opposite direction to the chosen coordinate system. However, in practical terms, weight is always a downward force due to gravity and is typically considered positive in magnitude.

39. What is the difference between static weight and dynamic weight?

Static weight is the weight of an object at rest, while dynamic weight refers to the apparent weight of an object in motion or under acceleration. Dynamic weight can be different from static weight due to inertial forces, which is important in designing structures subject to motion or vibration.

40. How does weight affect the concept of center of gravity?

The center of gravity is the average location of the weight of an object. It's the point where the entire weight of the body can be considered to act. Understanding the center of gravity is crucial in physics and engineering for analyzing stability and balance.

41. What is the relationship between weight and normal force?

The normal force is the force exerted by a surface on an object resting on it, perpendicular to the surface. On a horizontal surface under normal conditions, the normal force is equal and opposite to the weight, balancing it to prevent the object from sinking into the surface.

42. How does weight affect friction?

Weight plays a crucial role in friction. The force of friction is proportional to the normal force, which is often equal to the weight for objects on horizontal surfaces. This is why heavier objects typically experience more friction than lighter ones on the same surface.

43. How does weight relate to the concept of moment in physics?

Moment, or torque, is the rotational equivalent of force. It's calculated as the product of force (which can be weight) and the perpendicular distance from the axis of rotation. Understanding how weight contributes to moments is crucial in analyzing balance, levers, and rotational motion.

44. What is the significance of the weight-to-thrust ratio in aerospace engineering?

The weight-to-thrust ratio is crucial in aerospace engineering as it determines an aircraft's or rocket's ability to accelerate and climb. A lower ratio indicates better performance. It's calculated by dividing the total weight of the vehicle by the total thrust produced by its engines.

45. What is the relationship between weight and gravitational potential energy?

Gravitational potential energy is the energy an object possesses due to its position in a gravitational field. It's calculated as the product of the object's weight, the gravitational field strength, and the height above a reference point. This relationship is crucial in understanding energy transformations in gravitational fields.

46. What is the difference between true weight and apparent weight in a rotating frame of reference?

In a rotating frame of reference, like on a rotating planet, the apparent weight of an object differs from its true weight due to the centrifugal effect. The apparent weight is the vector sum of the true gravitational force and the centrifugal force. This difference is small on Earth but can be significant on rapidly rotating bodies.

47. How does weight affect the concept of mechanical advantage in simple machines?

Mechanical advantage in simple machines often involves manipulating weights or forces. For instance, in a lever, the mechanical advantage is the ratio of the output force to the input force, which can be weights. Understanding how weight interacts with mechanical advantage is crucial in designing and using tools and machinery.

48. How does the concept of weight apply in quantum mechanics?

In quantum mechanics, the classical concept of weight becomes less relevant at the subatomic scale. Instead, physicists work with concepts like mass-energy equivalence and gravitational interactions between particles. However, understanding how macroscopic weight emerges from quantum-scale interactions is an active area of research in quantum gravity.

49. What is the relationship between weight and the bending of light in general relativity?

In Einstein's theory of general relativity, gravity is described as the curvature of spacetime caused by the presence of mass and energy. While weight is a classical concept, the mass that gives rise to weight also causes this curvature. This leads to phenomena like gravitational lensing, where the path of light is bent by massive objects, effectively linking the classical concept of weight to the behavior of light in curved spacetime.

50. How does weight affect the period of a pendulum?

Interestingly, the weight of a pendulum bob does not affect its period. The period depends on the length of the pendulum and the local gravitational field strength, but not on the mass or weight of the bob. This counterintuitive fact is often a source of confusion for students.

51. How does the concept of weight apply in fluid dynamics?

In fluid dynamics, the weight of fluids plays a crucial role in phenomena like hydrostatic pressure, buoyancy, and fluid flow. The weight of a column of fluid creates pressure, and differences in fluid weight (due to density variations) can drive convection currents.

52. What is meant by "reduced weight" in physics problems?

"Reduced weight" typically refers to the apparent reduction in weight when an object is partially or fully submerged in a fluid. It's the difference between the object's true weight and the buoyant force exerted by the fluid. This concept is important in problems involving floating or submerged objects.

53. What is the significance of the weight distribution in structural engineering?

Weight distribution is crucial in structural engineering as it affects the stability, stress distribution, and load-bearing capacity of structures. Uneven weight distribution can lead to imbalances, increased stress in certain areas, and potential structural failures. Engineers must carefully consider weight distribution in designing buildings, bridges, and other structures.

54. What is meant by "specific weight capacity" in battery technology?

Specific weight capacity in battery technology refers to the amount of energy a battery can store per unit of its weight, typically expressed in watt-hours per kilogram (Wh/kg). This metric is crucial in applications where the weight of the power source is a critical factor, such as in electric vehicles or portable electronics.

55. How does the concept of weight apply in astrophysics, particularly in the study of stars and planets?

In astrophysics, the concept of weight is extended to the gravitational forces between celestial bodies. The weight of stellar material plays a crucial role in stellar structure and evolution. For planets, understanding their internal weight distribution is key to studying their composition, internal structure, and geological processes.

56. What is the relationship between weight and inertia?

While weight and inertia are related through mass, they are distinct concepts. Weight is the gravitational force on an object, while inertia is the object's resistance to changes in its state of motion. On Earth, we often use weight as a proxy for inertia because they're proportional, but this relationship doesn't hold in environments with different gravitational strengths.

57. How does weight affect the concept of buoyancy in different fluids?

Buoyancy depends on the weight of the fluid displaced by an object. In fluids of different densities, the same object will experience different buoyant forces. For example, an object may sink in water but float in a denser fluid like mercury, even though the object's weight remains constant.

58. What is the significance of the weight-to-power ratio in engineering?

The weight-to-power ratio is an important metric in various engineering fields, particularly in transportation. It's calculated by dividing the weight of a vehicle or machine by its power output. A lower ratio generally indicates better performance, as it means more power is available to move a given weight.