All About Ovulation Cycles

If you're wondering when you ovulate, you're certainly not alone. Ovulation cycles can be confusing. Learn how to calculate yours here.

Medically reviewed by Jessie Rubin, MD

If you're trying for a baby, you've probably learned two important facts about conception: 1) a person is most likely to conceive around the time of ovulation and 2) pinpointing the date of ovulation isn't always easy. That's because ovulation doesn't always happen like clockwork, especially if you are one of the many people who don't have a standard 28-day menstrual cycle. Ahead, find everything you need to know about when you might ovulate, with tips on figuring out your moments of peak fertility.

Related: How to Find Your Fertile Window When You're Trying to Conceive

The Phases of the Menstrual Cycle

Your menstrual cycle has four phases: menstrual, follicular, ovulation, and luteal. They each work together to form a pregnancy. Learn more about each phase below:

Menstrual Phase

Your menstrual cycle begins on the first day of your period. Since your body didn't get pregnant during your last cycle, it sheds its uterine lining, along with blood and mucus.

Follicular Phase

"This is where eggs grow inside a fluid-filled sac called a follicle," says Rashmi Kudesia, MD, an OB-GYN and reproductive endocrinology and infertility specialist at Houston Methodist and Houston IVF. A hormone called follicle-stimulating hormone (FSH) is behind the action. The one egg that develops most fully (the dominant egg) will ovulate in the next phase, says Dr. Kudesia.

Ovulation Phase

Ovulation happens when the ovary releases one mature egg into the fallopian tube, typically about halfway through one's menstrual cycle. The egg only survives about 12-24 hours in the reproductive tract. However, sperm survives in the fallopian tube for up to five days—meaning that a person has the greatest likelihood of conceiving on the day of ovulation and five days beforehand. (In rare instances, they body releases more than one egg, which can lead to fraternal twins).

Related: Ovulation Pain: What Does Mittelschmerz Feel Like?

The Luteal Phase

If sperm fertilized the egg during ovulation, it attaches to the uterine lining to form a pregnancy. If not, the egg is reabsorbed into the uterine lining and subsequently shed with a period. "The luteal phase extends from ovulation to the next period or a positive pregnancy test," explains Dr. Kudesia. "In general, the luteal phase is consistently two weeks long."

Related: What Happens During the Luteal Phase of the Menstrual Cycle?

A note about ovulation cycles and irregular periods

A "typical" menstrual cycle is anywhere from 21 to 35 days long. Very irregular periods may signal that you aren't ovulating regularly. If this applies to you, consider reaching out to an OB-GYN or health care provider for further assistance.

When Do I Ovulate?

Now that you know about the phases of your menstrual cycle, you're probably wondering when ovulation happens. "The luteal phase is generally about 14 days long. Since this part of the menstrual cycle is fairly stable, we can predict when ovulation occurs by subtracting 14 days from your last menstrual period," says Staci Pollack, an OB-GYN at the Division of Reproductive Endocrinology & Infertility at Montefiore Health System. In other words, individuals can expect to ovulate 14 days before the start of their next period.

Dr. Pollack says that figuring out your cycle length (with a tracking app or paper journal) can help you predict ovulation. Simply take your cycle length (28 days, 27 days, 30 days, etc.) and subtract 14 days. Here are some examples:

• Normal 28 day cycle = ovulation occurs around day 14

• 27 day cycle = ovulation occurs around day 13

• 30 day cycle = ovulation occurs around day 16

For those with unpredictable cycle lengths, the window of ovulation won't be consistent. "If your cycles are anywhere from 28-32 days, you will ovulate somewhere around day 14 to day 18," explains Dr. Pollack. Keep in mind that people are most likely to conceive on the day of ovulation and five days beforehand.

Of course, ovulation can be unpredictable, and the "14 day" concept isn't always accurate. Plenty of methods and tools exist to help birthing people calculate their most fertile days. These include ovulation predictor kits (OPKs), fertility monitors, basal body temperature (BBT) readings, cervical mucus monitoring, and more. As always, if you have any further questions or concerns about your ovulation cycle, be sure to consult an OB-GYN or health care provider.

Related: 8 Facts About Your Cycle and Conception

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