Enter the acceleration due to gravity (m/s^2) and the radius between the planet and object (m) into the Planet Mass Calculator. The calculator will evaluate and display the Planet Mass. 

Planet Mass Formula

The following formula is used to calculate the Planet Mass. 

PM = a*r^2 / G
  • Where PM is the Planet Mass (kg)
  • a is the acceleration due to gravity (m/s^2) 
  • r is the radius between the planet and object (m) 
  • G is the gravitational constant (6.67408*10^-11)

To calculate the mass of a planet, multiply the acceleration due to gravity by the radius between the planet and object squared, then divide by the gravitational constant.

How to Calculate Planet Mass?

The following example problems outline how to calculate Planet Mass.

Example Problem #1:

  1. First, determine the acceleration due to gravity (m/s^2).
    • The acceleration due to gravity (m/s^2) is given as: 9.81.
  2. Next, determine the radius between the planet and object (m).
    • The radius between the planet and object (m) is provided as: 500.
  3. Finally, calculate the Planet Mass using the equation above: 

PM = a*r^2 / G

The values given above are inserted into the equation below and the solution is calculated:

PM = 9.81*500^2 / 6.67408*10^-11 = 3.674e+16 (kg)

Example Problem #2: 

For this problem, the variables needed are provided below:

acceleration due to gravity (m/s^2) = 9.81

radius between the planet and object (m) = 6000

This example problem is a test of your knowledge on the subject. Use the calculator above to check your answer. 

PM = a*r^2 / G = ?