Track your menstrual cycle, calculate ovulation dates, and predict your next period. Understand your cycle phases and fertile window.
Phase: Follicular • Next period in 14 days
| Day of Cycle | 15 |
| Current Phase | Follicular |
| Predicted Ovulation | Mar 28 |
| Fertile Window | Mar 23 – Mar 29 |
| Next Period | Apr 12 |
| Days Until Next Period | 14 |
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Ovulation Day ≈ Cycle Length − 14 days
Fertile Window = Day (ovulation − 5) to day of ovulation
21–35 days. Average is 28 days. Cycle length can vary month to month.
Typically 14 days before the next period (not after previous). For a 28-day cycle, ovulation is around day 14.
5 days before ovulation + day of ovulation. Sperm survives up to 5 days; egg ~12 hours.
Depends on cycle regularity. Regular cycles (±2 days) are predictable. More data = better accuracy.
Stress, diet changes, exercise, thyroid issues, PCOS, hormonal birth control. See a doctor if varying >7 days.
Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.