Frequently Asked Questions
Everything you need to know about the Schwarzschild Radius Calculator.
What is the Schwarzschild radius?
The radius to which a mass must be compressed for its escape velocity to equal the speed of light, forming a black hole's event horizon.
How does this calculator work?
Pick a preset body or enter a custom mass in kg or solar masses, and it computes the radius instantly using r = 2GM/c².
Is it free?
Completely free, no sign-up, downloads, or limits.
What is Earth's Schwarzschild radius?
About 8.87 millimeters — roughly the size of a peanut.
What is the Sun's Schwarzschild radius?
About 2.95 kilometers.
Does a bigger mass mean a bigger black hole?
Yes, the Schwarzschild radius scales linearly with mass — more mass means a proportionally larger event horizon.
Can I enter mass in solar masses?
Yes, there's a unit toggle between kilograms and solar masses.
What happens if I enter a negative or zero mass?
The calculator rejects it with a clear validation message.
Is my data stored?
No; everything runs in your browser and isn't stored or sent anywhere.
Does it work on mobile?
Yes, fully responsive on all screen sizes.