Physical, Emotional & Intellectual Cycle Calculator
Plot your physical, emotional and intellectual biorhythms around any date on an interactive chart.
Processed entirely in your browser — nothing you enter here is ever uploaded.
Result
About this tool
Biorhythm theory rests on exactly three named cycles, and this page opens the calculator with that framing front and center: the 23-day physical cycle, the 28-day emotional cycle, and the 33-day intellectual cycle, each running as its own sine wave from the day you were born.
The physical cycle is traditionally read for strength, stamina and coordination; the emotional cycle for mood, sensitivity and creativity; the intellectual cycle for focus, memory and decision-making. The calculator computes all three exactly from the fixed 23/28/33-day periods and reports each as a percentage alongside a plain-language phase — high, low, or a critical day near the zero crossing — so you can compare the three side by side instead of guessing which one a single number belongs to.
None of this has held up under scientific scrutiny — studies have consistently found no predictive power in biorhythms — so the three cycles are best enjoyed as a structured, century-old curiosity rather than a diagnostic tool. Everything is computed locally in your browser from the fixed periods above; no birth data ever leaves your device.
Example. On the birth date itself the physical, emotional and intellectual cycles all read 0%.
Limit. The only periods are 23, 28 and 33 days, and each value is a sine rounded to a whole percent.