Accurately calculate weight of an object on the moon based on its Earth weight. Understand the physics of lunar gravity and how mass differs from weight.
Enter the weight on Earth (Mass).
Please enter a valid positive number.
Pounds (lbs)
Kilograms (kg)
Newtons (N)
Select the unit for your input.
Weight on the Moon
0.00 lbs
Formula: Earth Weight × 0.1654 (16.54% Gravity)
Weight Difference0.00 lbs Lighter
Percentage of Earth Weight16.54%
Effective Gravity1.62 m/s²
Figure 1: Comparison of Weight on Earth vs. Moon
Comparative Weight on Celestial Bodies
Location
Relative Gravity
Calculated Weight
Earth (Reference)
100% (1.0g)
0.00
Moon
16.5% (0.165g)
0.00
Mars
37.9% (0.379g)
0.00
Jupiter
252.8% (2.528g)
0.00
What is "calculate weight of an object on the moon"?
When you calculate weight of an object on the moon, you are determining the force exerted on an object's mass by the Moon's gravitational field. Unlike mass, which remains constant regardless of your location in the universe, weight is a variable force that depends entirely on local gravity.
This calculation is essential for astrophysicists, aerospace engineers planning lunar missions, and educators teaching the fundamental laws of physics. However, it is also a popular topic for curiosity—many people wonder how much they would weigh if they stood on the lunar surface.
Common Misconception: Many people believe they lose mass when they go to space. This is incorrect. Your mass (the amount of matter in your body) stays the same; only the gravitational pull (weight) changes.
Formula and Mathematical Explanation
To accurately calculate weight of an object on the moon, we use the ratio of the Moon's gravitational acceleration to Earth's gravitational acceleration. This is often simplified in basic physics as the "One-Sixth Rule," meaning you weigh about one-sixth on the Moon compared to Earth.
The Precise Formula
The mathematical formula is:
Wmoon = Wearth × (gmoon / gearth)
Variables Definition
Variable
Meaning
Typical Value
Wmoon
Weight on the Moon
Output Result
Wearth
Weight on Earth
User Input
gmoon
Moon's Gravity
~1.625 m/s²
gearth
Earth's Gravity
~9.807 m/s²
Ratio
Conversion Factor
~0.1654 (16.54%)
Table 1: Key Physics Variables for Lunar Weight Calculation
Practical Examples (Real-World Use Cases)
Example 1: The Apollo Astronaut
Consider an astronaut equipped with a heavy space suit. If the astronaut and suit combined weigh 360 lbs on Earth:
Earth Weight: 360 lbs
Calculation: 360 × 0.1654
Moon Weight: 59.54 lbs
This drastic reduction explains why astronauts in footage from the Apollo missions appear to bounce effortlessly across the lunar surface despite carrying heavy life-support equipment.
Example 2: A Lunar Rover
Engineers design a rover with a mass of 900 kg. On Earth, this rover weighs effectively 900 kg-force.
Earth Weight: 900 kg
Calculation: 900 × 0.1654
Moon Weight: 148.86 kg
While the rover is much lighter, its inertia remains that of a 900 kg object. This presents unique driving challenges: it accelerates and brakes slowly (due to high mass) but has less traction (due to low weight).
How to Use This Calculator
Enter Earth Weight: Input the current weight of the object or person in the "Earth Weight" field.
Select Unit: Choose between Pounds (lbs), Kilograms (kg), or Newtons (N). The calculator automatically adjusts the output label.
Review Results: The tool instantly displays the "Weight on the Moon" in the large blue box.
Analyze Differences: Check the "Weight Difference" to see exactly how much lighter the object becomes.
Compare: Use the comparison table to see what the object would weigh on Mars or Jupiter for context.
Key Factors That Affect Weight Calculation
When you calculate weight of an object on the moon, several physical factors ensure the accuracy of the result:
Gravitational Constant (G): The universal force of attraction between bodies. While constant everywhere, it dictates the local gravity based on planetary mass.
Planetary Mass: The Moon has significantly less mass than Earth ($7.35 \times 10^{22}$ kg vs $5.97 \times 10^{24}$ kg), resulting in weaker gravitational pull.
Planetary Radius: Gravity weakens with distance from the center of mass. Since the Moon is smaller, you are closer to its center, but its low mass still results in lower gravity.
Mass vs. Weight Distinction: This is the most critical financial and engineering factor. Transporting 1kg of gold to the Moon costs thousands of dollars based on mass (fuel needed to lift it), but once there, it weighs less on a scale. Its value (mass) remains unchanged.
Local Variations (Mascons): The Moon's gravity isn't perfectly uniform. Mass concentrations (mascons) beneath lunar basins can cause slight anomalies in local gravity, though our calculator uses the global average.
Centrifugal Force: On Earth, rotation slightly reduces apparent weight at the equator. The Moon rotates very slowly (once every 27 days), making this effect negligible compared to Earth.
Frequently Asked Questions (FAQ)
1. Does my mass change on the Moon?
No. Mass is the measure of matter in an object and is constant throughout the universe. Only your weight changes because weight is the force of gravity acting on that mass.
2. Is the 1/6th rule accurate?
It is a very close approximation. The precise ratio is roughly 16.54%, which is slightly less than 1/6th (16.66%). For precise engineering, you must calculate weight of an object on the moon using the exact 1.625 m/s² figure.
3. Why do things fall slower on the Moon?
Because the gravitational acceleration ($g$) is lower. On Earth, objects accelerate downwards at 9.8 m/s². On the Moon, they accelerate at only 1.62 m/s², making falls appear like "slow motion."
4. Can I jump higher on the Moon?
Yes. With the same leg strength (force), you can propel your body much higher because the downward force resisting your jump is significantly weaker.
5. How does this affect space travel costs?
Rocket equations depend on mass, not weight. Even though a satellite weighs less on the Moon, landing it there requires slowing down its mass. However, launching from the Moon is much cheaper than Earth because the escape velocity is lower.
6. Would a scale work on the Moon?
A spring scale (bathroom scale) would show your reduced weight accurately. A balance beam scale (comparing masses) would show the same "weight" as on Earth because the counterweights would also be affected by lower gravity equally.
7. What is the gravity on Mars compared to the Moon?
Mars has stronger gravity than the Moon but weaker than Earth. It is approximately 0.38g (38% of Earth's gravity), roughly double that of the Moon.
8. Do liquids weigh less on the Moon?
Yes, water and fuel weigh 16.5% of their Earth weight. This affects pump pressure requirements and fuel tank designs for lunar modules.
Related Tools and Resources
Explore more physics and astronomy calculators to deepen your understanding of celestial mechanics.