Free Schwarzschild Radius Calculator
Calculate the Schwarzschild radius (event horizon) of a black hole: r_s = 2 G M / c^2.
kg
Schwarzschild Radius
2,953.9938 m
Radius (km)2.9540 km
Mass (solar masses)1.0000 M_sun
Schwarzschild Radius vs Black Hole Mass
Schwarzschild Radius
The Schwarzschild radius defines the event horizon of a non-rotating black hole.
Formula
r_s = 2 G M / c²
For a solar-mass black hole, r_s ≈ 2.95 km. The radius scales linearly with mass.
Example Calculation
A 1-solar-mass black hole (M = 1.989e30 kg).
- 01r_s = 2 G M / c²
- 022 × 6.674e-11 × 1.989e30 = 2.654e20
- 03c² = (2.998e8)² = 8.988e16
- 04r_s = 2.654e20 / 8.988e16 ≈ 2953 m ≈ 2.95 km