Ovulation Calculator
Estimate when you are likely to ovulate in your current cycle and over the next few months.
The Ovulation Calculator is being built
This free calculator will appear here shortly. Meanwhile, the formula and ranges below show exactly how it works.
- First day of last period
- Average cycle length (days)
- Estimated ovulation date
- Fertile window
- Next 3 cycles
About the Ovulation Calculator
Ovulation is when an ovary releases an egg. Knowing your likely ovulation day helps when trying to conceive. It works best for fairly regular cycles.
Formula explained
Ovulation day ≈ next period start date − 14 days
which is the same as first day of last period + (cycle length − 14) days. The phase after ovulation (luteal phase) is usually about 14 days, so the timing of ovulation depends on your cycle length.
Frequently asked questions
Can I ovulate if my periods are irregular?
Yes, but it is harder to predict. Ovulation kits, basal body temperature tracking or a doctor’s scan help. Irregular cycles can also be a sign of PCOS or thyroid problems.
What are the signs of ovulation?
Clear, stretchy cervical mucus, a slight rise in body temperature after ovulation and, for some, mild one-sided lower belly pain.
Medical disclaimer: These tools give general information and estimates only. They are not a diagnosis and do not replace advice from a qualified doctor. Always talk to your doctor about your results, and seek urgent medical help in an emergency.