How Long Does Ovulation Last?

The best time to have sex to conceive varies

Ovulation lasts for 12 to 48 hours, but you are potentially fertile for up to seven days, and maybe up to 10 days, according to the most optimistic studies. This is because sperm can survive up to five days in the female reproductive tract.

Ovulation is when an egg is released from an ovary. That egg survives for up to 48 hours before it can no longer be fertilized by sperm. This short time may be considered the ovulation period. However, your total fertile period is how long the egg is fertile and how long sperm can wait for the egg combined. This is known as your fertile window.

While you are possibly fertile for seven days out of your cycle, the odds of conceiving at the far ends of that time period are small.

If you want to get pregnant, you should have sex one to three days before you ovulate.

how long does ovulation last
Illustration by Katie Kerpel. © Verywell, 2018.

Your Fertile Window: Odds for Getting Pregnant Before and After Ovulation

There have been many research studies on the best method of ovulation detection and on how fertile a woman is before and after ovulation. 

There are a few problems with studies like these. For one, there's no completely accurate method to detect the day you ovulated. At least, not at home.

It's possible for an ovulation predictor kit, a body basal temperature chart, and cervical mucus patterns to all indicate a slightly different ovulation day.

Ovulation can be detected with ultrasound or blood work, but this won't help you have sex on the right day. They can only tell you after you ovulated. (Plus, these require your doctor!)

Let's assume you know approximately when you ovulated, and you know how many days before or after ovulation you had sex. What are your odds of getting pregnant?

Here's what the research says. (This is based on several studies combined.) 

  • Five days before ovulation: 0.4 percent to 7 percent chance you'll conceive
  • Four days before ovulation: 8 percent to 17 percent 
  • Three days before ovulation: 8 percent to 23 percent 
  • Two days before ovulation: 13 percent to 29 percent
  • One day before ovulation: 21 percent to 34 percent
  • Ovulation day: 8 percent to 33 percent
  • One day past ovulation: 0.8 percent to 11 percent
  • Two days past: 3 percent to 9 percent 

Looking at the statistics above, you may notice that the odds vary greatly from day-to-day. For example, three days before ovulation, your odds of conceiving are anywhere from 8 percent to 23 percent. So why are there such large variations?

For one, each study used a different method of calculating ovulation day. This means one study's ovulation detection day may not match with another study's day.

Second, the studies were limited by the number of participants and conceived cycles. Just because someone can get pregnant the day before they ovulate doesn't mean they will.

Determining the Best Time to Have Sex to Conceive

So, your fertile window may last up to 10 days, but clearly, if you want to get pregnant, you want to have sex as close to ovulation as possible.

How can you time sex for your most fertile days during your fertile window?

There are many methods of tracking and predicting ovulation. Your best options include ovulation test kits (also known as OPKs, or ovulation predictor kits), body basal temperature charting, and checking for fertile cervical mucus. An ovulation day calculator may also help provide an estimate, but isn't always most accurate of methods.

That said, research has also found that timing sex for pregnancy can cause excessive stress in some couples. Timing sex for conception may be good for getting pregnant but not great for your relationship. That's important to consider.

According to the research, having sex when you have fertile raw-egg-white-like cervical mucus is the best way to time sex for pregnancy.

Another option is to have frequent sex and not worry so much about the exact ovulation day. But again, this can put more strain on a relationship than may be warranted and isn't a reassuring option for those who have been trying for some time or know there may be an underlying fertility problem.

Unless you are in the midst of fertility treatments, and your doctor has asked you to have sex on a particular day or set of days, you may want to consider dropping ovulation detection. 

Instead, have sex three to four times a week. You're bound to have sex during your fertile window. Will it be on your most fertile day? That may not occur. But it may not be necessary either.

How Can You Know If You're Not Ovulating?

If you're not ovulating, no amount of sex will get you pregnant. How can you know if you're ovulating or not?

Irregular periods or completely absent periods are the number one sign that ovulation may not be occurring, or may be occurring infrequently. It is possible to have regular periods and not be ovulating, but this is uncommon.

A Word From Verywell

While it's important to understand the science behind your fertility, try not to let the statistics ruin the fun. Find what works best for you and your partner.

If frequent unprotected sex doesn't get you pregnant after a year (or six months, if you're over 35), then see your doctor for a fertility evaluation. Of course, if you have any possible signs of a fertility problem (including signs that you may not be ovulating), you don't need to try to conceive for a year before you see your doctor. You can be proactive make that appointment now.

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Article Sources
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  1. Su HW, Yi YC, Wei TY, Chang TC, Cheng CM. Detection of ovulation, a review of currently available methods. Bioeng Transl Med. 2017;2(3):238-246. doi:10.1002/btm2.10058

  2. Cleveland Clinic, When should you have sex if you're trying to get pregnant? May 4, 2021.

  3. Stirnemann JJ, Samson A, Bernard JP, Thalabard JC. Day-specific probabilities of conception in fertile cycles resulting in spontaneous pregnancies. Hum Reprod. 2013;28(4):1110-6. doi:10.1093/humrep/des449

  4. Manders M, Mclindon L, Schulze B, Beckmann MM, Kremer JA, Farquhar C. Timed intercourse for couples trying to conceive. Cochrane Database Syst Rev. 2015;(3):CD011345. doi:10.1002/14651858.CD011345.pub2

  5. Boyle JA, Teede HJ. Irregular menstrual cycles in a young woman. CMAJ. 2014;186(11):850-2. doi:10.1503/cmaj.130667