Biorhythm Calculator

A biorhythm calculator charts three supposed cycles, physical, emotional and intellectual, that are said to run from the day you were born. Enter your birth date and, if you want a reading for another day, a target date as well. The calculator returns where each cycle sits on that date, expressed as a percentage between its peak and its trough. Biorhythms are a pop psychology idea rather than science, so treat the output as entertainment.