Ovulation & Fertile Window
Predict your most fertile cycle intervals. Our calculator follows ESHRE and ICMR standard safety frameworks to structure ovulation probability windows.
Configure Cycle Input
Average cycle length 28 days
Short (21) Default (28) Long (45)
Regular cycle pattern? If irregular, calendar timelines serve as loose guidelines only.
Awaiting Parameters
Enter the date of your last menstrual period and average cycle length to model your ovulation parameters.
Understanding Ovulation and Natural Conception
What is Ovulation?
Ovulation occurs when a mature egg is released from one of the ovaries, traveling down the fallopian tube for fertilization. This generally happens roughly 14 days before your next period starts. The day of ovulation, combined with the 5 preceding days, represents your **6-day fertile window**.
Tips for Tracking Your Ovulation
- Basal Body Temperature (BBT): Resting temperature drops slightly just before ovulation, followed by a sustained increase (about 0.5°C) immediately after.
- Cervical Mucus: Estrogen triggers thin, clear, stretchy mucus resembling raw egg whites, helping sperm survive.
- Ovulation Predictor Kits (OPKs): Home urine tests that detect the Luteinizing Hormone (LH) surge 24-36 hours before egg release.
Struggling to Conceive Naturally?
Read our diagnostics guide and compare leading IVF clinic chains.