Question

Formula on how to get charge between coulomb and joule

Answer 1

Are you looking for the relation between the two?

Answer 2

The electrostatic potential (voltage) [volts]

equals electrostatic potential energy [joules] ,
per charge [coulombs]

\[\large {V\,[\textrm V]}=\frac{U[\textrm J]}{Q[\textrm C]}\]

Equivalently:

The electrostatic potential energy [joules]

equals per charge [coulombs],
times electrostatic potential (voltage) [volts]

\[\large U[\textrm J] = Q[\textrm C]\cdot V\,[\textrm V]\]

Answer 3

so if you have the electric charge already, and you want the electric energy, , just multiply by the voltage