Ovulating means one of your ovaries is releasing an egg that can potentially be fertilized. It happens roughly once per cycle, typically around the midpoint, and it marks your most fertile time. The egg survives only 12 to 24 hours after release, which is why the timing matters so much for both getting pregnant and avoiding pregnancy.
What Happens Inside Your Body
Ovulation is the result of a carefully timed hormonal sequence. Early in your cycle, a hormone called FSH (follicle-stimulating hormone) prompts a small fluid-filled sac in one of your ovaries, called a follicle, to grow and mature with an egg inside it. As the follicle develops, it produces rising levels of estrogen, which eventually triggers a sharp spike in another hormone, LH (luteinizing hormone). This LH surge is the direct trigger for ovulation.
Once the LH surge happens, the follicle wall thins and eventually ruptures, releasing the egg. Interestingly, the egg stays mostly stationary inside the follicle during this whole process and only moves toward the rupture site in the final minutes before release. From there, the egg enters the fallopian tube, where fertilization can occur. The entire window for fertilization is narrow: the egg remains viable for just 12 to 24 hours. Sperm, on the other hand, can survive in the reproductive tract for 3 to 5 days, which is why sex in the days leading up to ovulation can still result in pregnancy.
When Ovulation Typically Happens
In a textbook 28-day cycle, ovulation falls around day 14, counting from the first day of your period. But a “normal” cycle can be anywhere from 21 to 35 days long, so ovulation timing varies significantly from person to person. It generally happens about halfway through your cycle, but the first half of the cycle (before ovulation) is the part that fluctuates most in length. Stress, illness, travel, and hormonal shifts can all push ovulation earlier or later in a given month.
One simple way to estimate your fertile window is the calendar method: look at your shortest and longest cycles over six months. Subtract 18 from the shortest cycle length and 11 from the longest. Those two numbers give you the range of days when you’re most likely fertile. For example, if your cycles run between 27 and 32 days, your fertile window would fall roughly between days 9 and 21.
Signs You’re Ovulating
Your body gives several signals around ovulation, though not everyone notices all of them.
Cervical mucus changes. This is the most reliable day-to-day sign. In the days leading up to ovulation, vaginal discharge becomes clear, slippery, and stretchy, often compared to raw egg whites. This texture helps sperm travel more easily. You’ll typically notice this slippery mucus for about three to four days. Before and after that window, discharge tends to be thicker, stickier, or pasty.
Ovulation pain. Some people feel a dull ache or sharp twinge on one side of their lower abdomen around the time the egg is released. This is called mittelschmerz. It may be caused by the growing follicle stretching the ovary’s surface, or by fluid from the ruptured follicle irritating nearby tissue. The pain usually lasts a few minutes to a few hours, though it can occasionally persist for a day or two. Some people experience it every cycle, others rarely or never.
Basal body temperature shift. After ovulation, your resting body temperature rises slightly, typically by 0.4 to 1.0°F (0.22 to 0.56°C). This shift confirms that ovulation has already occurred, so it’s more useful for pattern tracking over several months than for predicting ovulation in real time. You need to take your temperature first thing in the morning before getting out of bed for the readings to be meaningful.
How to Confirm You’re Ovulating
Ovulation predictor kits (OPKs) are urine tests that detect the LH surge. They’re approximately 99% accurate at picking up the surge, and ovulation typically follows one to two days after a positive result. This makes them the most practical at-home tool for pinpointing your fertile window in advance, unlike temperature tracking, which only tells you after the fact.
Combining methods gives you the clearest picture. Tracking cervical mucus helps you notice when fertility is approaching, an OPK confirms the LH surge, and temperature tracking over a few months shows whether you’re ovulating consistently.
Your Fertile Window
Because sperm can survive up to 5 days in the reproductive tract and the egg lives for only 12 to 24 hours, your fertile window is roughly 6 days long: the 5 days before ovulation and the day of ovulation itself. The highest chances of conception fall in the 2 to 3 days immediately before the egg is released, when both sperm survival and egg viability overlap. By the day after ovulation, the window has effectively closed.
When Ovulation Doesn’t Happen
Occasionally, a cycle passes without an egg being released. This is called anovulation, and it’s usually caused by hormonal imbalances. The most common reasons include polycystic ovary syndrome (PCOS), a very low body weight from restrictive eating or excessive exercise, and primary ovarian insufficiency, a condition where the ovaries stop functioning normally before age 40.
Irregular periods are the main clue that ovulation may not be happening consistently. Cycles that are significantly shorter than 21 days, longer than 35 days, or highly unpredictable in length can all point to anovulation. Keeping a record of your cycle length and symptoms, including changes in discharge, helps you spot patterns. If your periods are frequently irregular or absent, a healthcare provider can run blood tests and imaging to identify the cause and discuss options.