Biorhythm Calculator
| Date | Physical (%) | Emotional (%) | Intellectual (%) |
|---|
| Phase | Cycle position | Meaning |
|---|---|---|
| Rising | 0 – P/4 | Energy or mood builds toward a peak. |
| Peak | P/4 | Maximum positive influence and confidence. |
| Critical | P/2 | Zero crossing where rapid shifts may occur. |
| Low | 3P/4 | Minimum influence; reflection and rest. |
| Recovery | 3P/4 – P | Climbing back toward equilibrium. |
The biorhythm formula
Traditional biorhythm theory tracks three sine waves starting at birth. For any cycle with period and elapsed days , the value is computed with . The calculator multiplies the sine result by 100 to express each cycle as a percentage between -100% and +100%. Physical, emotional, and intellectual cycles use periods of 23, 28, and 33 days respectively.
Because the model ignores time zones and partial days, the interface treats each calendar day as a whole number. Enter any target date to see the current positions plus a rolling seven-day forecast. Critical days—where the value crosses zero—often signal faster swings, while peak days highlight opportunities for demanding activities.
Reading the results
The results panel lists percentage values and qualitative labels (high, low, or critical) to help interpret the cycles. Use the seven-day table to schedule workouts, creative sessions, or introspective breaks according to your personal belief in the rhythm model. You can also compare the three cycles for alignment: some followers treat simultaneous highs as favorable windows and simultaneous lows as reminders to slow down.
Consider pairing this calculator with the Sleep Cycle Calculator, Sleep Debt Calculator, and Caffeine Sleep Impact Calculator to see how rest and alertness planning intersects with perceived biorhythm swings.