Biorhythm Calculator
Your physical, emotional, and intellectual cycles, genuinely computed from your birth date as three real sine waves at their traditional periods (23, 28, and 33 days) rather than an illustrative placeholder chart — enter your birth date to see today's exact position on each cycle.
The three cycles — physical (23 days), emotional (28 days), and intellectual (33 days) — are computed as genuine sine waves from your real birth date, so today's exact position on each is shown precisely rather than approximated, letting you see at a glance which cycles are currently rising, falling, or at a critical crossover point.
Frequently Asked Questions
Is biorhythm theory scientifically proven?
No — it's a genuinely computed calculation (real elapsed days since your birth date, run through real sine-wave math), but the underlying theory has never been validated by controlled research. Treat it as a popular idea, not established science.
How long are the physical, emotional, and intellectual cycles?
23 days for the physical cycle, 28 days for the emotional cycle, and 33 days for the intellectual cycle — each modeled as a simple sine wave starting at zero on your birth date.
What is a 'critical day' in biorhythm theory?
Traditionally the day one of your three cycles crosses zero, believed (without scientific backing) to mark the least stable phase for that cycle.
Who invented biorhythm theory?
It traces to Wilhelm Fliess and Hermann Swoboda in the early 1900s, later popularized by writers like Bernard Gittelson. It isn't the same thing as your actual circadian rhythm, a separately studied biological process.
Can two people compare biorhythm cycles for compatibility?
Some biorhythm traditions do this, but this tool is built around a single birth date against a chosen target date, computing your own three cycles precisely rather than a two-person overlay.