Planet Mass Calculator

Understanding the mass of a planet is crucial in the field of astronomy and planetary science. The Planet Mass Calculator is a simple tool designed to help you determine the mass of a planet based on its gravitational acceleration and radius. This calculator is a valuable resource for students, educators, and anyone interested in learning more about planetary science.


Calculating the mass of a planet is not just an academic exercise; it has practical implications in various fields of science and engineering. Knowing a planet’s mass helps scientists understand its composition, structure, and the forces that govern its motion. It also aids in the study of planetary atmospheres, potential for life, and the planning of space missions. The Planet Mass Calculator makes this complex calculation accessible to everyone, fostering a deeper appreciation for the intricacies of our universe.

How to Use

Using the Planet Mass Calculator is straightforward:

  1. Input the Acceleration Due to Gravity: Enter the value of gravitational acceleration (in m/s²) experienced at the surface of the planet.
  2. Input the Radius: Enter the radius (in meters) from the center of the planet to the point where the gravitational acceleration is measured.
  3. Calculate: Click the “Calculate Planet Mass” button to get the result.

The calculator takes these inputs and performs the necessary calculations to provide you with the mass of the planet.

FAQs and Answers

  1. What is the gravitational constant (G)?
    • The gravitational constant (G) is a fundamental constant in physics that measures the strength of gravity between two objects. Its value is 6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻².
  2. Why do I need the radius and gravity to calculate planet mass?
    • The radius and gravitational acceleration are essential because they determine the gravitational force experienced at the planet’s surface, which directly relates to the planet’s mass.
  3. Can I use this calculator for any planet?
    • Yes, you can use this calculator for any planet, as long as you have the correct values for gravitational acceleration and radius.
  4. What units should I use for the radius and gravity?
    • The radius should be in meters (m), and the gravitational acceleration should be in meters per second squared (m/s²).
  5. Is this calculator accurate for small celestial bodies?
    • This calculator is primarily designed for planets, but it can be used for smaller celestial bodies with known gravitational acceleration and radius.
  6. Can I use this calculator for exoplanets?
    • Yes, as long as you have the necessary data for the exoplanet’s gravitational acceleration and radius.
  7. How precise are the results from this calculator?
    • The precision of the results depends on the accuracy of the input values for gravitational acceleration and radius.
  8. What if I only have the diameter of the planet?
    • If you have the diameter, you can divide it by 2 to get the radius and use that value in the calculator.
  9. Why is understanding a planet’s mass important?
    • Knowing a planet’s mass helps scientists study its composition, atmosphere, and potential for hosting life. It also aids in planning space missions.
  10. Can I use this calculator to compare different planets?
    • Yes, by inputting the gravitational acceleration and radius of different planets, you can compare their masses.


The Planet Mass Calculator is a handy tool that simplifies the process of calculating the mass of a planet. By inputting the gravitational acceleration and radius, users can quickly obtain the planet’s mass, making this tool invaluable for students, educators, and astronomy enthusiasts. Understanding the mass of planets enriches our knowledge of the universe and supports various scientific endeavors. Try the Planet Mass Calculator today and explore the wonders of planetary science with ease.