Watts and hertz measure different quantities, hence it is impossible to convert between them. Hertz measures frequency, which is the length of time needed to complete a cycle, whereas watts represent the amount of power being utilised. Electricity reverses direction in alternating current, and these cycles are measured in hertz.
The quantity of power that an appliance uses is unaffected by how long it takes for an alternating electric current to complete a cycle. The American power supply is rated at 60 hertz, which implies that a cycle of the current takes one-sixtieth of a second to complete.