Schwarzschild Radius Calculator

What is the Schwarzschild Radius?

The Schwarzschild radius (r_s) is the radius at which the escape velocity from a mass equals the speed of light. If any object is compressed below this radius, it becomes a black hole — light itself cannot escape.

r_s = 2GM/c²

• For Earth: r_s ≈ 8.9 mm (smaller than a marble)
• For the Sun: r_s ≈ 2.95 km
• For a human (70 kg): r_s ≈ 10⁻²⁵ m (sub-nuclear)

Black holes form when stellar collapse compresses a mass below its Schwarzschild radius — this requires roughly 3+ solar masses in a stellar-mass black hole.

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