Path A · Personal
Your biorhythm,
in 30 seconds.
Just your birth date. No signup. No email.
Privacy first. Mathematical calculations on 23, 28, and 33-day biological cycles.
Just your birth date. No signup. No email.
Privacy first. Mathematical calculations on 23, 28, and 33-day biological cycles.
A biorhythm is a classic model in which three fixed-length cycles start on the day you are born: physical at 23 days, emotional at 28, intellectual at 33. Each cycle spends half its time in a high phase and half in a low one, and is calculated from the birth date alone.
| Cycle | Length | What it reflects |
|---|---|---|
| Physical | 23 days | Energy, stamina, drive |
| Emotional | 28 days | Mood, sensitivity, patience |
| Intellectual | 33 days | Clarity, focus, decisions |
The curve sits above the centre line. The method links it to the days when that area responds best, so it is where you put whatever asks more of you.
The curve sits below the line. Not a bad day: it is the normal half of every cycle, the one where recovering beats pushing.
The curve crosses zero and switches phase. It is the least stable point of the cycle, the one the method flags for extra care. When two cycles cross on the same day it is called a double critical day.
Do I need the time of birth?
No. The three classic cycles are calculated from the date of birth alone.
Do I have to sign up to see the result?
No. The personal reading and the 7-day forecast are free and need no account and no email.
Is a biorhythm the same as a horoscope?
No. There are no zodiac signs and no planets involved: three fixed-length cycles calculated from your own day of birth, so different for every date.
How often do critical days happen?
Each cycle crosses zero twice per turn, so roughly every 11-12 days for the physical, every 14 for the emotional, every 16-17 for the intellectual. They rarely land together.
Is it spelled biorhythm or biorythm?
The correct spelling is biorhythm, often searched as biorythm or bio rhythm. In Italian it is bioritmo, in Spanish biorritmo.
The three classic cycles come out of more than a century of study on biological periodicity, from Wilhelm Fliess onward, a tradition that continues today as chronobiology. We present them for what they are: a framework for self-observation, not a diagnosis and not a forecast. The historical sources, including the critical ones.