Calculate your biorhythm

Physical cycle (23 days) — Shows your physical energy, strength and stamina. In high phases you feel vital and capable; in low phases you need more rest.

Emotional cycle (28 days) — Reflects your emotional stability, creativity and empathy. It influences relationships, mood and your ability to collaborate.

Intellectual cycle (33 days) — Affects your mental sharpness, focus and capacity to learn. In high phases, thinking and problem-solving come especially easily.

Critical days — When a curve crosses the zero line, you pass through a transition day. Birth Codex shows you when those days are due.

Biorhythm theory assumes that three fixed cycles run from your birthday onward: a physical one of 23 days, an emotional one of 28 days and an intellectual one of 33 days. Each cycle starts at zero, rises into the positive half, falls into the negative and begins again — much like a sine wave.

The calculation is simply the number of days that have passed since your birth, divided by the length of each cycle. The remainder of that division determines where on the wave you stand today. Nothing more is needed — no zodiac signs, no time of birth.

What matters is the right expectation: the physical cycle describes strength, stamina and resilience, the emotional one mood and sensitivity, the intellectual one concentration and quickness of mind. They run independently of one another and overlap anew each day.

The most attention goes to the so-called critical days. That is the moment when a cycle crosses the zero line — switching from the positive into the negative range, or the other way around. At such transitions the area in question is considered less stable.

A critical physical day doesn't mean something will happen to you. It is more of a reminder not to overestimate yourself: plan your reserves tightly, dose your exercise more carefully, get enough sleep. A critical emotional day invites you not to hold important conversations under time pressure.

Treat these days as a gentle nudge, not a ban. Anyone who knows the cue plans appointments, exams or demanding undertakings more deliberately — and still decides for themselves what they feel up to.

The biorhythm is a simplified model, not a law of nature. Scientifically, the rigid assumption of fixed 23-, 28- and 33-day cycles is unproven — real bodily rhythms such as the sleep-wake cycle follow light, hormones and habits, not your date of birth.

Even so, the model has a practical value: it forces you to pause regularly and look consciously at your current state. This small routine of self-observation often does more than the numbers themselves.

So use the curves as a prompt, not a prediction. Don't confuse them with medical diagnostics, and don't make health decisions on their basis alone. As a tool for more mindfulness in everyday life, the biorhythm stays light and easy to apply.