Calculate the event horizon radius of a non-rotating black hole for any given mass.
Object Mass
Event Horizon Radius
Enter mass to calculate radius
Quick Reference
GGravitational Constant (6.6743 × 10⁻¹¹)
MMass of the object in kg
cSpeed of Light (299,792,458 m/s)
RsSchwarzschild Radius
Overview
The Schwarzschild radius (Rs) is the physical distance from the center of a non-rotating object at which the escape velocity equals the speed of light. If an object is compressed to fit within this radius, it becomes a black hole.
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Pro Tips
The Schwarzschild radius is directly proportional to the mass of the object.
This formula assumes the black hole is not rotating (Schwarzschild) and has no electric charge.
For a black hole the size of the Sun, the radius is only about 3 kilometers.
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Fun Facts
"To turn the Earth into a black hole, you would need to compress it into a sphere the size of a marble (about 9 millimeters)."
"Karl Schwarzschild derived this solution to Einstein's field equations in 1916 while serving in the German army during World War I."
"The density of a black hole with a mass of 4.5 billion Suns would be about the same as the density of water."
