How it works
Fill in the 2 fields above and Surface Gravity Calculator calculates the result instantly, recalculating as you change any value. It applies the formula g = GM/r². The math runs locally in your browser — nothing is sent to a server.
Formula
g = GM/r²Examples
- Mass 5.97e+24 kg, Radius 6371000 m → Surface gravity: 9.8162 m/s²
Frequently asked questions
How do I use the Surface Gravity Calculator?
Enter your values in the 2 input fields and the result is calculated automatically as you type. Change any value to see the numbers update instantly.
What formula does the Surface Gravity Calculator use?
It uses g = GM/r². The calculation is performed in your browser using standard, well-established math for accurate results.
Is my data private?
Yes. The Surface Gravity Calculator runs entirely in your browser. Nothing you enter is uploaded, saved to a server, or shared — it never leaves your device.
Is the Surface Gravity Calculator free?
Yes, it is completely free with no sign-up, no limits and no watermarks. Like every tool on astronomy and the rest of the platform, you can use it as often as you like.
Popular in Astronomy
Telescope Max Magnification Calculator
Find the maximum useful magnification of a telescope.
Orbital Period Calculator
Calculate orbital period from semi-major axis (Kepler’s third law).
Parallax Distance Calculator
Calculate a star’s distance from its parallax.
Redshift Velocity Calculator
Estimate recession velocity from redshift.