Ovulation

What ovulation is and why timing matters

Ovulation is the release of a mature egg from an ovary, and it is the single most important event in the menstrual cycle for anyone trying to conceive. The egg is only viable for about 24 hours after release, but because sperm can survive in the reproductive tract for up to five days, the practical fertile window spans roughly six days: the five days before ovulation plus the day itself.

Where ovulation falls in a typical cycle

In a 28-day cycle, ovulation usually happens around day 14, counting the first day of your period as day 1. But cycle length varies a lot between people and even from month to month for the same person, so ovulation shifts earlier in shorter cycles and later in longer ones. What tends to stay more consistent is the luteal phase, the stretch between ovulation and the next period, which is usually close to 14 days. That makes counting backward from your next expected period, once you know your typical cycle length, a useful way to estimate when ovulation likely happened.

Recognizing the signs

Common signs include a change in cervical mucus (becoming clearer, stretchier, and more slippery, often compared to raw egg white), a small rise in basal body temperature after ovulation, mild one-sided pelvic twinges some people notice, and a positive result on an ovulation predictor kit, which detects the surge in luteinizing hormone shortly before the egg is released. No single sign is perfectly reliable on its own, which is why many people track more than one. See Ovulation Signs and Symptoms for a full breakdown of what to watch for.

Tracking methods, compared

Ovulation predictor kits are generally the most reliable at-home option for most people, since they detect the hormone surge directly. Basal body temperature tracking confirms ovulation has already happened rather than predicting it in advance, so it is more useful for understanding your pattern over time than for timing a single cycle. Apps and calendar tracking can offer a helpful estimate once you know your typical cycle length, but they are less precise for anyone with irregular cycles. See Ovulation Tracking: Apps and Tests for a closer comparison of what each method does well.

Practical checklist for tracking ovulation

When to talk to a provider

See a provider if your cycles are consistently shorter than 21 days or longer than 35 days, if you are not getting a clear ovulation signal after a few months of tracking, or if you have symptoms like unusually heavy or painful periods, which can sometimes point to conditions like PCOS or endometriosis that affect ovulation.

How these guides fit together

Use the signs and symptoms guide to know what your body might be telling you, the tracking apps and tests guide to pick a method that fits your routine, and the myths guide to clear up some of the common misconceptions that make ovulation feel more complicated than it needs to be; see Ovulation Myths.

Frequently asked questions

How many days after my period do I ovulate?

It depends on your cycle length, but for a typical 28-day cycle, ovulation usually happens around day 14. In a shorter or longer cycle, ovulation shifts earlier or later accordingly, since the luteal phase after ovulation is fairly consistent at about 14 days.

How long is the fertile window?

About six days: the five days before ovulation and the day of ovulation itself. This is because sperm can survive in the reproductive tract for several days, while the egg is only viable for about 24 hours after release.

Do ovulation predictor kits actually work?

Yes, for most people. They detect the surge in luteinizing hormone that happens shortly before ovulation, which is a reliable predictor. They can be less accurate for people with irregular cycles or certain hormonal conditions like PCOS.

For more on cycle tracking and fertility, see the ACOG guidance on evaluating infertility.