🕳️ Schwarzschild Radius Calculator
Calculate the Schwarzschild radius of any mass, the radius its event horizon would have if it collapsed into a black hole.
What the Schwarzschild radius is
The Schwarzschild radius is the radius that a given mass would need to be compressed within for its escape velocity to equal the speed of light, forming a black hole with an event horizon at that radius. Any mass has a theoretical Schwarzschild radius, even everyday objects, though only extremely dense masses like collapsed stars actually reach this state.
The formula
The Schwarzschild radius is calculated as r_s = 2GM / c², where G is the gravitational constant (6.6743 × 10⁻¹¹ m³/(kg·s²)), M is the mass, and c is the speed of light (299,792,458 m/s). You can enter mass directly in kilograms or in solar masses (1 solar mass ≈ 1.98892 × 10³⁰ kg), a common unit in astrophysics.
For reference, Earth’s Schwarzschild radius is about 8.87 millimeters, and the Sun’s is about 2.95 kilometers. This tool is for general educational and study purposes.