Ovulation Calculator
Predict your fertile window and ovulation dates for the next 3 months.
Understanding Your Fertile Window
An egg is viable for only 12-24 hours after ovulation. However, sperm can survive in the reproductive tract for up to 5 days. This means intercourse in the 5 days before ovulation can still result in fertilization. The combined "fertile window" is approximately 6 days.
Signs of Ovulation
Physical signs include cervical mucus becoming clear and slippery (egg-white consistency). Basal body temperature rises slightly (0.2-0.5 F) after ovulation. Some women feel mild one-sided pelvic pain (mittelschmerz). An LH surge (detected by ovulation predictor kits) occurs 24-36 hours before ovulation.
Irregular Cycles
This calculator assumes regular cycles. Irregular cycles (varying by more than 7-9 days) make ovulation prediction less reliable. PCOS, stress, weight changes, and thyroid issues can cause irregular cycles. Track your cycles over several months for a better baseline. If trying to conceive, use our due date calculator once you have a positive test.