Calculate Weight Force

Online calculator and formulas for calculating weight force and mass

Weight Force Calculator

Calculate gravitational force

Calculates the Weight force (F) from Mass (m) and Earth's acceleration (g). Weight force indicates how strongly a body presses downward.

N
kg
m/s²
Standard Earth acceleration: 9.81 m/s²
Result
Force:
Mass:

Example Calculation

Example: Weight of a person
Problem:

A person has a mass of 75 kg. What is the weight force of this person on Earth (g = 9.81 m/s²)?

Given:
  • Mass m = 75 kg
  • Earth's acceleration g = 9.81 m/s²
  • Find: Weight force F
Solution:
\[F_g = m \times g\]
\[F_g = 75 \text{ kg} \times 9.81 \text{ m/s}^2\]
\[F_g = 735.75 \text{ N}\]
Gravity at different locations
Earth (Equator): g ≈ 9.787 m/s²
Earth (Poles): g ≈ 9.832 m/s²
Moon: g ≈ 1.62 m/s²
Mass vs. Weight

Mass is the same everywhere (75 kg), but weight (weight force) changes depending on the gravitational field:

On Earth: \[F = 75 \text{ kg} \times 9.81 = 735.75 \text{ N}\] On the Moon: \[F = 75 \text{ kg} \times 1.62 = 121.5 \text{ N}\]

Formula for weight force

Weight force is the force with which a body is pulled downward due to gravity. It depends on the mass and the local gravitational acceleration.

Calculate weight force

Basic formula for calculating weight force from mass and Earth's acceleration.

\[\displaystyle F_g = m \cdot g\]
Fg = Weight force [N]
m = Mass [kg]
g = Earth's acceleration [m/s²]
Calculate mass

Rearrangement of the basic formula to calculate mass.

\[\displaystyle m = \frac{F_g}{g}\]
Mass results from weight force divided by Earth's acceleration.
Important Notes
  • Weight force is location-dependent and changes with gravity
  • Mass remains the same everywhere, weight (weight force) does not
  • 1 Newton = 1 kg·m/s² (force that accelerates 1 kg at 1 m/s²)
  • On Earth: g ≈ 9.81 m/s², on the Moon: g ≈ 1.62 m/s²

Detailed description of weight force

Physical Fundamentals

With this function, weight force or mass can be calculated. Force is generally understood as an action on a body that increases, decreases, changes the direction of its velocity, or deforms it.

The weight force calculated here indicates how strongly a body presses or is pulled downward.

Usage Instructions

To calculate, select with the radio buttons whether force or mass should be calculated. Then enter the corresponding value and click the 'Calculate' button. The default value of 9.81 corresponds to the average value of gravity on Earth.

Application Areas

Engineering

Static calculations, structural planning, foundation design. Important for calculating loads and stresses.

Science and Research

Physical experiments, material testing, space travel. Foundation for many scientific calculations.

Everyday Life and Technology

Scales, elevators, cranes, vehicle loading. Everywhere weights play a role.

Understanding Gravity

How strong exactly the weight force is depends on the mass and the location factor g. Depending on where you are, the weight force is of different strength:

Earth (Equator)

g ≈ 9.787 m/s²
For 75 kg person:
\[F = 75 \times 9.787 = 734 \text{ N}\]

Earth (Poles)

g ≈ 9.832 m/s²
For 75 kg person:
\[F = 75 \times 9.832 = 737 \text{ N}\]

Moon

g ≈ 1.62 m/s²
For 75 kg person:
\[F = 75 \times 1.62 = 122 \text{ N}\]

Conclusion: Mass remains the same, but on the Moon you weigh only about 1/6 as much as on Earth!