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Ovulation Window Calculator
Know your exact fertile window, ovulation day, and per-day conception probability — backed by clinical research. Designed by Dr. Neha Sain.
Enter the very first day of your most recent period.
28 days
21 days (short)28 days (average)45 days (long)
🇮🇳 India note: PCOS affects an estimated 20–25% of Indian women and is a leading cause of irregular ovulation and fertility challenges. If your cycles vary widely month to month, Dr. Neha can help evaluate and support your fertility.
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Enter your last period date above
Your ovulation window, fertile days, and next 3 cycle projections will appear here — instantly, for free.