Watts can not be "converted" to Amps but there is a formula for calculating Watts, Amps, Ohms or Volts. This is called "Ohms Law". To calculate Amps or Watts, you must have a known Voltage. Watts are Amps times Volts for example.
120 Volts Times 30 Amps equals 3600 Watts. Understand?
120 Volts Times 30 Amps equals 3600 Watts. Understand?