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Free event-horizon radius calculator for astrophysics and relativity learning. Estimate Schwarzschild radius from mass and compare the result in SI and solar-mass context.
Last updated: April 20, 2026
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Radius (meters)
2.953339e+3
Radius (kilometers)
2.953339
Mass in solar masses
1.000000e+0
Escape speed at radius
299,792,458 m/s
Interpretation
The Schwarzschild radius is 2.953339 km. At this radius, escape velocity equals the speed of light.
Model note:
Uses the ideal Schwarzschild solution (non-rotating, uncharged mass) from general relativity.
Formula
Rs = 2GM / c^2
Reference
M / M_sun
Condition
vesc = c at Rs
Solar mass input (M = 1 M_sun)
Radius (km)
2.953339
Mass (solar masses)
1.000000
This calculator applies the Schwarzschild metric radius relation for spherically symmetric non-rotating masses. It provides event-horizon scale estimates and supporting context for relativistic gravity studies.
Rs = 2GM / c^2G is gravitational constant, M is mass, and c is speed of light in vacuum.
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