Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship:
where I is the current through the conductor in units of amperes, V is the voltage measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm’s law states that the R in this relation is constant, independent of the current.
Basically, Ohm’s Law defines the relationship between power, voltage, current, and resistance. The chart below gives an idea of what wattage to expect for sub ohm vaping, but you should always use a calculator to double check your work before firing a coil.