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
Dec 22, 2016Dec 18, 2016 - Dec 28, 2016Sep 15, 2017
Jan 19, 2017Jan 15, 2017 - Jan 25, 2017Oct 13, 2017
Feb 16, 2017Feb 12, 2017 - Feb 22, 2017Nov 10, 2017
Mar 16, 2017Mar 12, 2017 - Mar 22, 2017Dec 8, 2017
Apr 13, 2017Apr 9, 2017 - Apr 19, 2017Jan 5, 2018
May 11, 2017May 7, 2017 - May 17, 2017Feb 2, 2018

* 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.