Biorhythm
From your birth date, we chart the physical, emotional, and intellectual cycles to read today's condition.
Charts three body rhythms from your birth date to read today’s condition. The idea began with the German physician Wilhelm Fliess at the end of the nineteenth century and settled into the three curves of 23, 28 and 33 days around the middle of the twentieth. No scientific basis has been established for these cycles predicting how body or mind will actually be. Treat it as the pleasure of seeing a rhythm drawn out rather than a forecast.
How it works
We count the days from your birth to today and place you on three cycles: physical at twenty-three days, emotional at twenty-eight, and intellectual at thirty-three. The reading shifts a little every day.
What you'll get
You see where each cycle stands and whether it is high, low, or at a critical turn, a graph of the week either side of today, and an overall condition combining all three. Enter the hour you were born as well and the graph you see is recalculated to that hour.
Twenty-three, twenty-eight and thirty-three did not arrive together
What Wilhelm Fliess put forward at the end of the nineteenth century was two cycles, of twenty-three and twenty-eight days. The thirty-three-day cycle standing for the intellect was added later, in the twentieth century. The three curves were never a single set from the outset; they were laid on one at a time across decades. The combination of twenty-three, twenty-eight and thirty-three now in wide use settled in around the middle of the last century.
Fifty-eight years before the three line up again
The three numbers do not divide into one another, so returning to exactly the state you were born in takes as long as all three multiplied together. That comes to twenty-one thousand two hundred and fifty-two days, or a little over fifty-eight years. It is something a person might live through once, if at all. It is also why days with all three curves high, or all three low, come round so rarely.
Watch the direction rather than the number
Whether today is rising or falling is more useful than what percentage it reads. At the same value, a point on the way up means the coming days are better, while a point on the way down means today is the better part of that week. That is why the week either side is shown alongside. Rather than taking a single number as a report card for the day, watching which way the curve is headed helps a good deal more when arranging a schedule.
Why it survives without any evidence behind it
The arithmetic is simple and the result appears as a graph, which makes it feel like something you can hold. On top of that, checking back on a day when you felt poor easily turns up a low stretch, while the days you felt fine during a low stretch leave no mark on memory. Only the hits get remembered, so the sense that it works is always inflated well beyond the fact. Knowing that shape lets you enjoy the graph far more lightly.
Do not use this graph as grounds when unwell
We would not want anyone brushing off how they feel as a low stretch and noticing a real problem late. Pain that runs for days, difficulty falling asleep, a mood that stays down for a long time: none of that is something a curve can account for. In such cases please close this page and see a doctor. The graph belongs where it prompts you to check in on your body and mind once, and no further.
Frequently Asked Questions
Why do the numbers shift a little every day?
Because today's position moves each day along the 23, 28, and 33-day curves that have run since your birth.
What does a critical day mean?
It is the day a curve crosses zero and turns from rising to falling or back. It is read as a wobbly day, so it is wise not to push.
Is there scientific evidence for biorhythms?
No. The claim that fixed cycles govern how you feel has not held up to testing. As a prompt to check in with your body and mind for a moment it still works, so treat it as entertainment.
Should I do nothing on a low day?
Not at all. A low stretch reads as a time to conserve and recover. Rather than postponing what matters, it suits putting finishing and tidying in place of an overloaded schedule.
What changes if I enter my birth time?
The curves shift in phase by that much. Biorhythms are counted from the moment of birth, so someone born at midnight and someone born late at night read differently on the same day — the physical cycle can differ by more than twenty percentage points. Leave the time unknown and the calculation runs from midnight, so you can still read it.
Does entering a lunar date change the curves?
It does. The three cycles count the days elapsed from your birth to today, and choosing lunar converts the date first and counts from there. A shift of only a few days moves your position on the 23, 28 and 33-day cycles, which changes today's percentages — so stay with whichever you chose first.