Biorhythm calculator
Chart your physical, emotional and intellectual cycles from your birth date.
Biorhythm calculator
Paste your birth date and this tool plots the three classic biorhythm cycles — physical (23 days), emotional (28 days) and intellectual (33 days) — as sine-wave percentages for a chosen target date. Each cycle swings between +100% and -100% on its own rhythm, and the report shows exactly where all three sit today, or on any date you pick.
Set the target date to look at a specific day instead of today, and use forecast days to control how far ahead the ASCII graph runs (3 to 60 days). Each cycle gets its own row of characters — from "#" at a strong high through "." near the midline down to "=" at a strong low — so you can scan a stretch of days at a glance and see where a cycle is rising, falling or about to flip. Critical days, where a cycle crosses zero, are called out separately, since that transition is the traditional point of unpredictability in biorhythm theory. Turn on the overall average option to add a single combined score across all three cycles.
The birth date and target date must be in YYYY-MM-DD format; anything else returns a calm error explaining the expected shape rather than a silent wrong answer. Because the underlying formula is a simple sine wave keyed to a day count, results are exact and reproducible for the same two dates, and the tally line always shows total days lived, the critical-day count in the current forecast, and the combined average.
Everything runs locally in your browser — your birth date is never uploaded or sent anywhere. Copy the report, download it as a .txt file, or clear the input and start over; nothing you type here is stored beyond your own device.