Event Horizon (Schwarzschild) Radius Calculation

Calculate Schwarzschild Radius for given gravitational constant, light speed and body mass.




A region in space which does not allow anything to pass out with such a gravity pull is called as the black hole.

The radius of the boundary of such an event horizon (hole) is called as the schwarzschild or the gravitational radius.


rs = 2GM / c2


rs = Black Hole Schwarzschild Radius,

G = Constant of Gravitation,

M = Mass of Body,

c = Speed of Light

Schwarzschild radius

The Schwarzschild radius is also known as gravitational radius.

In 1916, the German astronomer Karl Schwarzschild calculated this exact solution for the theory of general relativity.

The Schwarzschild radius of an object is proportional to the mass, for example following table shows the mass and redius of few objects:

Object Mass Schwarzschild radius
Sun 2.0 × 1030 kg 3 km
Earth 6.0 × 1024 kg 8.7 mm
Moon 7.3 × 1022 kg 0.11 mm
Neutron Star 2.8 × 1030 kg 4.2 km
Jupiter 1.9 × 1027 kg 2.2 m

The Schwarzschild obtained the exact solution to Einstein's field equations for the gravitational field outside a non-rotating, spherically symmetric body.

Event horizon (Schwarzschild radius) just marks the radius of a sphere past which we can get no information, no particles and no light.

The distance computed from the mass of an object is called Schwarszhild radius and the event horizon is a region of space-time.

A non-rotating black hole has an event horizon whose size is the Schwarzschild radius of the black hole.

We can compute the Schwarzschild radius for any object using this calculator.