Ovulation Calculator
Track your fertility window and ovulation cycle to understand your reproductive health better.
Cycle Information
Count from the first day of one period to the first day of the next
How many days does your period typically last?
How it works
Ovulation typically occurs 14 days before your next period. Your fertile window includes the 5 days before ovulation and the day of ovulation.
Understanding Ovulation
Ovulation is when your ovary releases an egg. This typically happens around day 14 of a 28-day cycle, but can vary based on your individual cycle length.
- The egg can be fertilized for 12-24 hours
- Sperm can live in your body for up to 5 days
- Your fertile window is about 6 days long
Signs of Ovulation
- Changes in cervical mucus (clear, stretchy)
- Slight increase in basal body temperature
- Mild pelvic pain (mittelschmerz)
- Positive ovulation predictor kit result
Tracking Tips
- Track your cycle for at least 3 months
- Note any symptoms or changes
- Use multiple tracking methods
- Consider lifestyle factors
This will not stop you getting pregnant
These dates are a prediction from your average cycle length — no ovulation test, no temperature, no other sign. Calendar-based methods are the least reliable form of contraception there is: in ordinary use, roughly one in four people relying on them are pregnant within a year, and a calculator like this one is weaker still, because a cycle that arrives a few days early moves every date on this page. If you are trying not to conceive, use a method that does not depend on predicting the future, and talk to a doctor about which one fits you.
Important Note
This is an estimate from average cycle patterns, and it assumes ovulation lands 14 days before your next period. Individual cycles vary, and the fertile window shown here — the five days before ovulation plus ovulation day — reflects how long sperm survive, not how long the egg lasts. Ovulation tests or basal body temperature will tell you far more about your own body than any prediction can.
Related Health Tools
Cycle Length Calculator
Calculate your average menstrual cycle length and patterns.
Try Calculator →Due Date Calculator
Calculate your baby's expected due date and track pregnancy milestones.
Try Calculator →