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Schwarzschild Radius Calculator

2.95km radius
2953 mRadius (m)
5.9 kmDiameter

The Schwarzschild radius marks the event horizon of a non rotating black hole, the boundary from inside which not even light can escape. It is given by two times the gravitational constant times the mass, divided by the speed of light squared. Remarkably, any mass compressed below this radius becomes a black hole, so you can compute the horizon for anything from the Sun to the Earth to yourself. This calculator accepts a mass in kilograms or in solar masses and returns the radius in meters and kilometers, plus the diameter for scale. The Sun would need to shrink to about three kilometers across to become one. Everything is computed locally in your browser.

Frequently asked questions

What is Schwarzschild Radius Calculator?

The Schwarzschild radius marks the event horizon of a non rotating black hole, the boundary from inside which not even light can escape. It is given by two times the gravitational constant times the mass, divided by the speed of light squared.

Is Schwarzschild Radius Calculator free to use?

Yes. Schwarzschild Radius Calculator is completely free, with no sign-up and no usage limits.

Does Schwarzschild Radius Calculator work in a web browser?

Yes. Schwarzschild Radius Calculator runs in any modern web browser. There is nothing to download or install.

Is my data private with Schwarzschild Radius Calculator?

Yes. Schwarzschild Radius Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.