I wrote the Planetary Gravity Calculator while out between Colonia and Sag A*. When jumping into a system, I would honk and check out the system map while frame shift drive is charging. On occasion, I would see a cool ringed planet that I want to know the gravity of. Obviously, I can use the detailed surface scanner to get this info, but that is a lot of commitment to fly out to a planet that is >5k ly away if I don't want to risk landing. What this tool does is allow you to enter the earth masses and radius of the planet and determine the amount of gravity on that planet before leaving the star.
Basically the program determines the gravity of a planet using the same formula used to determine gravity on earth. I just substituted in values of the planet in question. The formula generates the acceleration due to gravity on that planet ( Earth is 9.8m/s^2 ) It then compares the generated number for the planet against earths number to give you the 'Planetary Gravity' as E:D gives you when you're crashi...er landing on a planet.
source: http://www.dummies.com/education/scienc ... s-surface/
You can find this tool at https://b00st3d.github.io/