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Schwarzschild Radius Calculator

Event horizon radius r_s = 2GM / c².

Compute the Schwarzschild (event horizon) radius of a non-rotating black hole from its mass using r_s = 2 · G · M / c², and report the result in metres, kilometres, and AU.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

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Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

r_s = 2 · G · M / c², G = 6.674·10⁻¹¹ m³/(kg·s²), c = 2.998·10⁸ m/s.

In depth

Compute the Schwarzschild (event horizon) radius of a non-rotating black hole from its mass using r_s = 2 · G · M / c², and report the result in metres, kilometres, and AU.