Calculator Input
Use preset masses or enter a custom value. The calculator handles kilograms, grams, solar masses, Earth masses, Jupiter masses, and pounds.
Plotly Graph
The chart shows Schwarzschild radius versus mass on logarithmic axes, plus your selected point when a calculation is available.
Example Data Table
These reference values help compare familiar masses with their corresponding event horizon scales.
| Object | Mass | Mass in kg | Schwarzschild radius | Diameter |
|---|---|---|---|---|
| Earth | 1 Earth masses | 5.972200e+24 kg | 8.870103 mm | 17.740206 mm |
| Sun | 1 Solar masses | 1.988470e+30 kg | 2.953339 km | 5.906679 km |
| Jupiter | 1 Jupiter masses | 1.898130e+27 kg | 2.819164 m | 5.638327 m |
| 10-solar-mass object | 10 Solar masses | 1.988470e+31 kg | 29.533394 km | 59.066788 km |
| Sagittarius A* scale | 4.300000e+6 Solar masses | 8.550421e+36 kg | 0.08489 AU | 0.16978 AU |
Formula Used
Here, G is the gravitational constant, M is mass, and c is the speed of light. The calculator assumes a non-rotating, uncharged object, matching the standard Schwarzschild solution.
How to Use This Calculator
- Choose a preset object or enter your own object label.
- Enter the mass value using standard or scientific notation.
- Select the correct mass unit from the dropdown.
- Optionally enter an observation radius to test time dilation outside the horizon.
- Click the calculate button to show the result above the form.
- Review the table, summary cards, and graph for quick interpretation.
- Use the CSV button for spreadsheet-ready export.
- Use the PDF button to save a clean calculation report.
Frequently Asked Questions
1) What is the Schwarzschild radius?
It is the radius of the event horizon for a non-rotating, uncharged mass. If all mass fits inside that radius, light cannot escape to distant observers.
2) Does a larger mass always give a larger radius?
Yes. Schwarzschild radius increases linearly with mass. Doubling the mass doubles the event horizon radius, provided the same non-rotating Schwarzschild assumptions remain valid.
3) Can Earth become a black hole naturally?
Not under normal conditions. Earth would need to be compressed inside a Schwarzschild radius of only a few millimeters, which is far beyond natural planetary behavior.
4) Why does the calculator include photon sphere and ISCO?
They provide extra physical context. The photon sphere marks unstable light orbits, while ISCO gives the smallest stable circular orbit for matter around a non-rotating black hole.
5) What does the average density result mean?
It is the mass divided by the volume of a sphere with radius Rs. It helps compare how compact an object must be to form an event horizon.
6) Is the time dilation factor valid everywhere?
No. This simple factor applies only outside the event horizon for a stationary observer. At or below the horizon, a stationary position is not physically possible.
7) Does this calculator handle spinning black holes?
No. It uses the Schwarzschild model only. Rotating black holes follow the Kerr solution, which changes horizon properties and orbit locations.
8) Why is Hawking temperature included?
It adds an advanced thermodynamic estimate. The temperature is extremely tiny for stellar and supermassive black holes, but it is useful for theory comparisons.