This calculator is designed to allow you to determine a stable orbit for a specific distance from the body.

This program knows the mass and diameters of common solar system bodies.

The main difference here is the distance is in Kilometers instead of miles.

a = G*m/r²   v = square root (a*r)

a = acceleration (meters/sec/sec)
G = Gravitational constant (6.6732E-11)
m = mass (Kg)
r = radius (meters)
v = velocity (meters/sec)