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

Your Results

Days since birth

13062

Physical

-52%

Emotional

Intellectual

-91%

Mini trend (14 days)

Physical

Emotional

Intellectual

Critical day

Critical Days (zero crossing)

Previous: 2025-10-05

Next: 2025-10-06

For entertainment only; see disclaimer.

7‑Day Outlook

Date	Phys	Emo	Intel
2025-10-06	Low	Critical	Low
2025-10-07	Mid-	Mid-	Low
2025-10-08	Critical	Low	Low
2025-10-09	Mid+	Low	Low
2025-10-10	High	Low	Low
2025-10-11	High	Low	Mid-
2025-10-12	High	Low	Critical

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
Enter dates
Birth date and target date
2
Compute days since birth
Target - Birth
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.