Ovulation itself is nearly instant, taking only a few seconds for your ovary to release an egg. But the window where that egg can actually be fertilized lasts 12 to 24 hours. Most people asking this question really want to know how long they can get pregnant around ovulation, and that fertile window is about six days total.
How Long the Egg Survives
Once your ovary releases an egg, it travels into the fallopian tube and stays viable for 12 to 24 hours. If sperm doesn’t reach it in that time, the egg breaks down and gets absorbed by your body. This is a surprisingly short lifespan compared to sperm, which can survive inside the reproductive tract for three to five days. That mismatch between egg and sperm survival is what creates the larger fertile window.
Your Actual Fertile Window
Because sperm can wait around for days, you can conceive from sex that happens well before the egg is released. Your realistic fertile window spans roughly five days before ovulation and the day of ovulation itself. The highest-probability days are the two days right before you ovulate. Research published in Obstetrics & Gynecology found that sex one day before ovulation increased the likelihood of pregnancy by about 18.5%, and sex two days before ovulation increased it by 23.6%.
Sex on the day of ovulation itself can also result in pregnancy, but the odds start dropping because the egg’s clock is already ticking. Sex more than five days before ovulation rarely leads to conception because most sperm won’t survive long enough.
What Triggers Ovulation
Ovulation is set off by a surge in luteinizing hormone (LH), which you can detect with over-the-counter ovulation test strips. The egg is typically released 24 to 36 hours after this surge begins, or roughly 16 to 17 hours after LH hits its peak. This is why ovulation kits are useful for timing: a positive result means ovulation is likely within the next day or so, putting you right at the start of your most fertile hours.
In a textbook 28-day cycle, ovulation tends to fall around day 14. But cycles vary widely. If your cycle is 32 days, you likely ovulate closer to day 18. If it’s 26 days, it may be around day 12. The second half of the cycle (from ovulation to your next period) is more consistent at about 14 days, so counting backward from your period length gives a rough estimate.
Signs That You’re Ovulating
Your body gives a few signals around ovulation, though none are perfectly reliable on their own.
- Cervical mucus changes: As ovulation approaches, vaginal discharge becomes wet, stretchy, and slippery, resembling raw egg whites. This type of mucus typically lasts three to four days and makes it easier for sperm to travel. When it dries up or turns sticky again, ovulation has likely passed.
- Basal body temperature: Your resting temperature rises by less than half a degree Fahrenheit (about 0.3°C) after ovulation. The catch is that this shift only confirms ovulation after it’s already happened, so it’s more useful for tracking patterns over several cycles than for predicting fertile days in real time.
- Ovulation pain: Some people feel a mild ache or twinge on one side of the lower abdomen, sometimes called mittelschmerz. It doesn’t happen to everyone and can be easy to miss.
Combining methods gives you the clearest picture. Tracking mucus changes helps you spot the lead-up to ovulation, LH test strips confirm it’s imminent, and temperature tracking verifies it happened.
Can You Release More Than One Egg?
Some cycles involve the release of two or more eggs, a process called hyperovulation. When this happens, the eggs are released within the same ovulation window, typically within 12 to 36 hours of each other. If both eggs are fertilized, the result is fraternal twins. Hyperovulation is more common in people with a family history of fraternal twins, those over 35, and those with a higher body mass index. It doesn’t extend your fertile window in any meaningful way since the second egg is released so close to the first.
Putting the Timeline Together
Here’s the practical summary. The egg exists for 12 to 24 hours. Sperm survive for three to five days. Your best chance of conception comes from sex in the two days before ovulation. If you’re trying to conceive, aim for every one to two days during the five days leading up to expected ovulation and the day of ovulation itself. If you’re trying to avoid pregnancy, the fertile window requires at least six days of caution, and more if your cycles are irregular and ovulation timing is harder to predict.