Kinetic Energy = 0.5mass multiplied by velocity squared
using metric units - 1 Joule = 1kg *(metres/seconds) squared
chuck in a constant and the same equation will allow you to use any units you like, in theory you could have an equation reading something like
1 Mars bar = 1 double decker bus * (width of a 2p/a blink of an eye) squared * by constant C