Enter the radius of the event horizon (km) into the Black Hole Mass Calculator. The calculator will evaluate and display the Black Hole Mass.

## Black Hole Mass Formula

The following formula is used to calculate the Black Hole Mass.

**BHM = R / 3**

- Where BHM is the Black Hole Mass (solar mass units)
- R is the radius of the event horizon (km)

## How to Calculate Black Hole Mass?

The following example problems outline how to calculate Black Hole Mass.

Example Problem #1:

- First, determine the radius of the event horizon (km).
- The radius of the event horizon (km) is given as: 13,000,000.

- Finally, calculate the Black Hole Mass using the equation above:

BHM = R / 3

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

BHM = 13,000,000 / 3 = 4,333,333.33 (solar mass units)

Example Problem #2:** **

For this problem, the variables needed are provided below:

radius of the event horizon (km) = 10,000,000

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

BHM = R / 3** = ?**