Ovulation & Fertility Calculator
Calculate your ovulation day, high-fertility windows, and probability of conception.
Fertility Inputs
Thursday, Sep 17, 2026
Calculated based on your last period date and a luteal phase length of 14 days. Real ovulation timing can shift based on stress, sleep, or hormones.
Day-by-Day Fertile Window & Conception Probabilities
Gender Conception Theory (The Shettles Method)
The Shettles method proposes that male sperm (Y-chromosome) are faster but more fragile, while female sperm (X-chromosome) are slower but more resilient.
Intercourse should take place 2 to 4 days before ovulation. fragiler Y sperm die off, leaving resilient X sperm when egg is released.
Intercourse should take place as close to ovulation as possible. Swift Y sperm are more likely to reach the egg first.
*Disclaimer: The Shettles method is an educational theory with scientific debate. True chance is approximately 50/50 for any conception event.
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