# How big are supermassive black holes?

##### 1 Answer

May 26, 2016

Supermassive black holes are surprisingly small.

#### Explanation:

The supermassive black hole at the centre of our galaxy is about the size of our solar system. The radius of a black hole is described by the Schwarzschild radius:

Where R is the radius of the black hole, G is the gravitational constant, M is the mass of the black hole and c is the speed of light.