Ovulation Calculator
Ovulation is when an ovary releases an egg — the most fertile point of your cycle — and it happens about 14 days before your next period. Enter your last period and cycle length to see the ovulation day and fertile window for the coming months.
Your numbers
Result
- Fertile window
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- Next period
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How the ovulation day is estimated
Ovulation lands roughly 14 days before the next period starts, so the estimate is ovulation = cycle start + (cycle length − 14). On a 28-day cycle that is about day 14; on a 32-day cycle, about day 18. The fertile window covers the 5 days before ovulation plus the day after, because sperm can survive several days while the egg lives about one.
Planning across several cycles
The table projects the next three cycles so you can plan ahead. Because real cycle length varies from month to month, treat the dates as estimates — the more regular your cycle, the more reliable they are. Logging the start of each period for a few months sharpens the prediction considerably.
Signs that confirm ovulation
Your body gives clues beyond the calendar: cervical mucus turns clear and stretchy near ovulation, basal body temperature rises a few tenths of a degree just after, and some people feel a light one-sided twinge. Drugstore ovulation tests detect the LH hormone, which surges shortly before you ovulate — useful when cycles are irregular.
Informational and educational result. Not a substitute for professional advice.
Frequently asked questions
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