Ovulation Calculator

The Ovulation Calculator estimates the ovulation date and the corresponding due date if the pregnancy is based on normal biological cycles. It is not recommended to avoid pregnancy based on ovulation calculation.

First Day of Your Last Period:
Average Length of Cycles:

Most Probably*Ovulation WindowEstimated Due Date if Pregnant
Feb 20, 2016Feb 16, 2016 - Feb 26, 2016Nov 13, 2016
Mar 19, 2016Mar 15, 2016 - Mar 25, 2016Dec 11, 2016
Apr 16, 2016Apr 12, 2016 - Apr 22, 2016Jan 8, 2017
May 14, 2016May 10, 2016 - May 20, 2016Feb 5, 2017
Jun 11, 2016Jun 7, 2016 - Jun 17, 2016Mar 5, 2017
Jul 9, 2016Jul 5, 2016 - Jul 15, 2016Apr 2, 2017

* This date is based on the average of 14 days before the next period was due.

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Ovulation is the process by which a mature ovarian follicle ruptures and discharges one or a few eggs in a female's menstrual cycle. This process is controlled by the brain via the release of the luteinizing hormone (LH) and the follicle-stimulating hormone (FSH). If the egg is fertilized by sperm, it may implant from 6 to 12 days later, at which point pregnancy begins.

The average ovulation time is 14 days before the first day of your next period. However, the ovulation day may vary among women. Therefore, cycle length alone is not a reliable indicator of your ovulation day. Ovulation tests are more accurate, having a 99% accuracy rate, and they can be purchased without a prescription.

Normally, ovulation test kits measure the LH level in urine. A surge of the LH level, or a "positive" test result indicates the onset of ovulation and the fertilization windows, which occur during the following three days.