What Is Your Schwarzschild Radius?

The Schwarzschild radius is the critical radius at which an object’s gravity becomes so strong that not even light can escape. So, if any mass is compressed within this radius, it would form a black hole.

This calculator lets you explore that concept by entering the mass of any object — from planets and stars, to hypothetical supermassive bodies or smaller objects like Your favourite car, smartphone and … yes — even Yourself. You can instantly calculate the Schwarzschild radius of everything.

The formula is based on Einstein’s theory of general relativity:

Rs = 2GM / c²

where:

• G is the gravitational constant
• M is the object’s mass
• c is the speed of light

For comparison:

• Earth’s Schwarzschild radius is only about 9 millimeters
• The Sun’s is roughly 3 kilometers

So have fun and use the calculator to see how gravity scales across the universe — from microscopic black holes to supermassive cosmic objects.