Kilograms to Newtons Converter Calculator
Free convert mass (kg) to weight/force (n) using f = mg. calculate weight from mass and gravitational acceleration.
Input Parameters
Earth: 9.80665 m/s², Moon: 1.62 m/s², Mars: 3.71 m/s²
Results
Enter mass to calculate weight
What is the Difference Between Mass and Weight?
Mass is the amount of matter in an object (measured in kg) and is constant everywhere. Weight is the force of gravity acting on that mass (measured in N) and varies with gravitational acceleration.
On Earth, 1 kg of mass weighs approximately 9.81 N. On the Moon, the same 1 kg mass weighs only 1.62 N because gravity is weaker. The mass remains 1 kg, but the weight (force) changes.
This distinction is crucial in physics and engineering. Mass determines inertia (resistance to acceleration), while weight determines the gravitational force acting on an object.
Mass to Weight Formula
Where:
- • F = Weight/Force (N)
- • m = Mass (kg)
- • g = Gravitational acceleration (9.80665 m/s² on Earth)
Note: This is Newton's second law: F = ma, where a = g (gravitational acceleration).
How to Convert Kilograms to Newtons
-
1
Identify the mass
Determine the mass in kilograms that you want to convert to weight.
-
2
Determine gravitational acceleration
Use 9.80665 m/s² for Earth, or the appropriate value for other celestial bodies.
-
3
Apply the formula
Calculate F = m × g
Practical Examples
Example 1: Earth Weight
A 10 kg object on Earth. Calculate its weight.
Solution:
F = m × g = 10 kg × 9.80665 m/s²
F = 98.07 N
Example 2: Moon Weight
The same 10 kg object on the Moon (g = 1.62 m/s²). What is its weight?
Solution:
F = 10 kg × 1.62 m/s²
F = 16.2 N (much lighter!)
Applications
Space Missions
Understanding how weight changes on different planets and in space, while mass remains constant.
Engineering
Calculating loads, forces, and structural requirements based on mass and gravitational forces.
Weighing Systems
Understanding how scales measure weight (force) but are calibrated to display mass for convenience.
Education
Teaching the fundamental difference between mass and weight, and Newton's laws of motion.
Frequently Asked Questions
Why is 1 kg not equal to 1 N?
Mass (kg) and force (N) are different physical quantities. 1 kg of mass weighs approximately 9.81 N on Earth due to gravity. The conversion factor is g = 9.80665 m/s².
Does weight change with location?
Yes! Weight (force) changes with gravitational acceleration. At higher altitudes or on different planets, weight changes, but mass remains constant.
What is the weight of 1 kg on Earth?
1 kg of mass weighs approximately 9.81 N (or about 2.2 lb) on Earth's surface. This is the standard conversion: 1 kg → 9.80665 N.
Why do we use "weight" in everyday language?
On Earth, weight and mass are proportional (F = mg), so scales calibrated for Earth's gravity display mass. This is why we say "weigh 70 kg" even though we're measuring force.
What happens in zero gravity?
In zero gravity (free fall or space), weight becomes zero (F = m×0 = 0), but mass remains unchanged. Objects are weightless but still have mass and inertia.