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Biorhythm Calculator

Enter your birth date to see physical (23), emotional (28), and intellectual (33) cycle strengths for any date. Prefilled with a typical example.

Calculate Your Biorhythm

Birth Date
Target Date

Your Results

Days since birth
13109
Physical
-27%
Emotional
90%
Intellectual
100%
Mini trend (14 days)
+100%0%-100%
Physical
Emotional
Intellectual
Critical day
Critical Days (zero crossing)
Previous: 2025-11-17
Next: 2025-11-22

For entertainment only; see disclaimer.

7‑Day Outlook
DatePhysEmoIntel
2025-11-22Mid-HighHigh
2025-11-23CriticalHighHigh
2025-11-24Mid+HighHigh
2025-11-25HighHighHigh
2025-11-26HighHighHigh
2025-11-27HighHighHigh
2025-11-28HighHighHigh

Labels: High (≥ +33%), Low (≤ −33%), Critical (near zero crossing or |value| ≤ 5%).

Biorhythm Formula & Interpretation

Sine Wave Cycles

Physical: sin(2π × days / 23)
Emotional: sin(2π × days / 28)
Intellectual: sin(2π × days / 33)
📈 Positive Values

Above-average potential for the cycle

  • • Favorable days for related tasks
  • • Peak near +100%
⚠️ Critical Days

Near zero crossings; transitions

  • • Unstable trend
  • • Extra caution suggested

How to Calculate Biorhythm

Steps

1) Compute days since birth
2) Apply sine cycles for 23/28/33 days
3) Convert to percentages

Calculation Steps:

  1. 1
    Enter dates
    Birth date and target date
  2. 2
    Compute days since birth
    Target - Birth
  3. 3
    Apply cycles
    23 / 28 / 33 day sine cycles

Important Considerations

⚠️ Disclaimer

Biorhythm is not medical advice and lacks strong scientific validation. Use for entertainment only.

📅 Date Precision

Use correct birth date for consistent results

  • • Time zones ignored
  • • Start-of-day alignment
🔁 Cycle Periods

23/28/33 days are conventional periods

  • • Physical, Emotional, Intellectual
  • • Sine wave from birth
➕/➖ Interpretation

Positive/negative reflects trend potential

  • • Not guarantees
  • • Consider context
🧪 Evidence

No strong empirical support

  • • Treat as entertainment
  • • Avoid critical reliance

Example Cases

Case 1: Birth 1990-01-01, Today

Inputs: Birth: 1990-01-01
Target: Today
Outputs: Physical: varies
Emotional: varies
Intellectual: varies

Use Case: Quick daily check of cycle tendencies.

Case 2: Planning a Presentation

Inputs: Birth: 1995-06-15
Target: 2025-10-01
Outputs: Physical/Emotional/Intellectual: percentages

Use Case: Check intellectual and emotional cycles for an upcoming task.

Tips

  • Compare multiple dates to observe cycle patterns.
  • Avoid over-reliance; use as a reflective guide.

Frequently Asked Questions

What is a biorhythm?
Biorhythm theory models physical (23 days), emotional (28 days), and intellectual (33 days) cycles as sine waves starting at birth to estimate daily performance tendencies.
How do I use this calculator?
Enter your birth date and optionally a target date. Submit to see today’s or the selected date’s cycle strengths as percentages.
What do positive and negative values mean?
Positive values indicate above-average potential in that area; negative values indicate below-average. Zero crossings are transition days and may feel unstable.
Is biorhythm scientifically proven?
Biorhythms are a popular concept but lack strong scientific backing. Treat results as entertainment or a self-reflection tool, not medical advice.
Can I predict critical days?
Critical days occur near zero crossings of cycles. Some users avoid high-stakes tasks on such days, but decisions should consider broader context and evidence.

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