How do you calculate rms current?

Power is determined from an AC voltage measured in volts RMS and an AC amperage measured in amps RMS, but there is really no such thing as "RMS power". People are using the term "RMS power", but that is not correct. it is actually "average power".

Why there is no such thing as 'RMS watts' or 'watts RMS' and never has been:

http://www.hifi-writer.com/he/misc/rmspower.htm