Peak Ovulation Day [How to Maximize Your Fertility]

Do you want to know how to determine your peak ovulation day to maximize your fertility?

Then you are in the right place!

In this post you are going to learn:

  • What is peak ovulation,
  • How long your fertility window lasts for each month,
  • The best days to have sex to optimize your chances of getting pregnant.

Are you ready?

Let’s get started.

peak-ovulation-day cover image

When are you fertile?

You are fertile for up to 5 days before you ovulate and up to 24 hours after ovulation.

It is only during this time each month that you can get pregnant.

Shocking, I know!

What this means is that you must have vaginal intercourse during this window to optimize your chances of getting pregnant.

fertile-window is 5 days before ovulation and 1 day after ovulation

What is peak ovulation?

Peak ovulation is the time at which you are most fertile, meaning your chances of becoming pregnant are at their highest.

Peak ovulation occurs 1-2 days before your body releases an egg, and the day that it is released.

In general, peak ovulation occurs approximately 14 days before your next period starts.

What Causes The Egg To Be Released?

Each month, your body prepares for fertilization by recruiting and releasing one egg into your uterus.

It does this by growing ovarian follicles, each of which contains an egg.

Ultimately, only one follicle will continue to grow and become the dominant follicle.

Once that single follicle reaches a sufficient size, this will trigger your body to release really high levels of a hormone known as luteinizing hormone, or LH for short.

This is also known as “The LH surge.

The LH surge is what ultimately causes the egg to be released, or ovulated.

The really high level of LH that occurs is known as peak ovulation.

Once the egg is released, it can only survive in the female reproductive tract for 12-24 hours.

So get moving, the clock is ticking!

Do you ovulate the day after The peak?

So how long after the LH surge do you ovulate?

Most women will ovulate 1-2 days after the peak (aka the LH surge), with an average of about 36 hours.

Is peak ovulation before or after your period?

Peak ovulation occurs before your period.

Every month, your body undergoes a cycle to prepare for the fertilization of an egg. If fertilization does not occur, you will get a period and restart the cycle.

Let’s go through each step individually.

image of the female menstrual cycle with ovulation in between the follicular phase and luteal phase
  • The day you bleed is cycle day # 1
  • Day 1 starts the follicular phase of your menstrual cycle
  • During the follicular phase, your ovary begins to grows one dominant follicle which contains the egg that will be ovulated/released
  • The LH surge occurs once the follicle is big enough, triggering ovulation ~36 hours later
  • This is the most fertile day of your cycle
  • After ovulation, you start the luteal phase of your menstrual cycle
  • The follicle that ovulated the egg becomes a corpus luteum (hence the name luteal phase)
  • If no pregnancy occurs the corpus luteum regresses, and this causes your endometrium to shed- which is why you get a menstrual period again

A Simple Peak Ovulation Calculator (For Natural Family Planning)

The best way to calculate peak ovulation is to take a look at the length of your period.

In general, most women will ovulate 14 days before their period.

So if your periods are normally 30 days, you will ovulate around day 16.

Now, since you are most fertile, 1-2 days prior to ovulation, you would subtract 1-2 days from day 16.

So it would look like this:

(Average menstrual cycle length) – (14 days) – (1 or 2 days)

Another example:

If you have 28-day cycles, you can calculate your peak ovulation by using this formula:

(28) – (14 days) – (1 or 2 days) = 12 or 13

Days 12 and 13 of your cycle are going to be when you are most fertile. (Don’t forget, Day 1 of your cycle is the day you start bleeding).

You can also use an ovulation calendar to better determine your average menstrual cycle length.

An Even Easier Method – The Ovulation Test

Instead of calculating your ovulation, there is an easier way to determine your peak fertility.

You can use an ovulation predictor kit (OPK) to determine the best time to have intercourse.

These devices can detect if there are high levels of LH in your urine. The good news is, studies have confirmed that these tests are reliable in predicting your high fertility days.

Clearblue is the most well known and the one I recommend.

You can get them here on Amazon.

Once you have a positive result on the OPK, it’s time to have intercourse! This is what we mean when we say timed intercourse.

However, you still need to have a general idea of what days you should check the test, or else you will be going through a ton of kits.

If you have a 28-day cycle, begin checking the test strips nightly on Day 10.

If your cycles are longer than 28 days, you can add a day based on how much longer your cycles are and vice versa.

How long does ovulation last?

Ovulation is instant.

However, the egg that gets released through ovulation only survives for 12-24 hours.

The egg must travel to the fallopian tube and be fertilized by sperm within this time frame.

ovulation occurs when the dominant follicle gets released from the ovary

If the egg does not get fertilized by a sperm within this time frame, you have missed your fertile window this cycle.

How long after ovulation can you conceive?

You can only conceive 12-24 hours after ovulation.

However, it is possible to conceive 1-2 days before ovulation because sperm can survive in the female reproductive tract for 3-5 days!

Do you ovulate in the morning or night?

Research shows that the LH surge occurs in the evening to early morning.

Once you have ovulated, you have 12-24 hours for your egg to be fertilized by sperm.

Therefore, you should have intercourse that evening as well as the next morning to optimize your chances of getting pregnant.

How do I know ovulation is over?

The most common indicators of ovulation include:

  • changes in your cervical mucus,
  • an elevation in your basal body temperature,
  • elevations of serum progesterone levels

Peak fertility is associated with slippery and clear mucus.

When ovulation is over, the cervical mucus will become sticky and thick which prevents sperm from getting to the uterus.

You may even experience days where there is very little to no discharge.

Another way to detect that ovulation is over is by checking your basal body temperature.

Your body temperature will increase by about 0.5 degrees celsius AFTER you ovulate.

This is very difficult to truly detect, and very impractical.

Additionally, a blood test looking at progesterone levels will also confirm if ovulation has occurred or not.

Other Related Question

How long after the LH surge do you ovulate?

Ovulation occurs anywhere from 24-38 after the start of the LH surge.

As such, it is important to check ovulation predictor kits at least 2 days before you think you will ovulate.

What is high fertility vs peak fertility?

High fertility refers to the time period where your estrogen levels begin to climb, about ~3-4 days before the LH surge.

Peak fertility is when your LH surge has started.

Some predictor kits will show a flashing smiley face for high fertility and a solid face for peak fertility.

How many days of high fertility can you have before the peak?

High fertility usually lasts about 3-4 days before the peak day, and it reflects the rise in estrogen levels that occur before ovulation.

I have a solid smiley face, when will I ovulate?

A solid smiley face indicates that your LH levels are elevated.

In general, you will ovulate 24-38 hours after the peak, aka the solid smiley face.

How long does sperm survive in the female body?

Sperm could survive in the female body for up to 5 days.

sperm-could-survive in the female body-for-5-days

However, some sperm may die before 5 days depending on the conditions in the female reproductive tract, mainly the vagina, cervix, uterus, and fallopian tubes.

In particular, certain types of birth control will cause the female reproductive system to become inhospitable for sperm resulting in sperm death.

If I ovulate in the morning can I get pregnant that night?

An egg survives for about 12-24 hours after ovulation. As long as you have intercourse before the 24-hour mark, you have a chance of getting pregnant.

Can I get pregnant at the peak of ovulation?

Yes, you can get pregnant from intercourse that occurs on your peak LH day. In fact, this is the day where you are most fertile.

Can I get pregnant 2 days after ovulation?

It is possible for you to get pregnant 2 days after ovulation, but it is very unlikely.

Typically you are fertile only up to the day of ovulation.

What does ovulation discharge look like?

Ovulation discharge is very wet and stretchy.

Some will refer to this type of discharge as a raw egg white appearance.

The reason for this very wet discharge is so that sperm can easily enter the cervix and travel up the uterus to meet and fertilize the egg.

What are the signs of a woman not ovulating?

The most common sign that you are not ovulating is irregular or infrequent periods.

A normal menstrual cycle is 21-35 days.

If you have cycles that last longer than 35 days, (some women have 60+ day cycles), you are not ovulating.

What are the reasons why you are not ovulating?

The most common cause of why you are not ovulating is your hormonal profile.

The most common causes of irregular cycles or anovulatory cycles are:

  • Polycystic ovarian syndrome or PCOS
  • Hypothyroidism (low thyroid hormone levels)
  • Hyperprolactinemia (high prolactin levels)
  • Being severely underweight with a BMI <18.5

If you have any of these conditions, please speak with your medical provider as they are all treatable!

When should I see a fertility specialist?

You should consult a fertility doctor if you have been unable to achieve pregnancy after:

  • 12 months of regular unprotected intercourse if you are under 35 years
  • 6 months of regular unprotected intercourse if you are over 35 years
  • Immediately if you are 40 years or over
  • Immediately if you have a known diagnosis that causes infertility

Final Words on Finding Your Peak Fertility

So there you have everything you need to know about ovulation and the optimal timing to get pregnant.

The fertile period spans 3-5 days before you ovulate and ends on the day of ovulation.

Isn’t it so interesting how there are only a few fertile days each month in which you could get pregnant?

Share this with anyone who can benefit from fertility awareness!

Now I want to hear from you.

Are you planning your pregnancy based on your ovulation?

Are you going to use an ovulation test?

Comment below and let me know!

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Brittany Robles, MD, MPH, CPT

Brittany Robles is a full-time OBGYN physician, a NASM certified trainer, and a prenatal and postnatal fitness specialist. She holds a Master of Public Health degree in maternal health with a special interest in exercise and nutrition. She is also the co-author of The White Coat Trainer. Learn more about her here.

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  1. Stanford JB, Dunson DB. Effects of sexual intercourse patterns in time to pregnancy studies. Am J Epidemiol. 2007 May 1;165(9):1088-95. doi: 10.1093/aje/kwk111. Epub 2007 Feb 8. PMID: 17289774.
  2. Wilcox A.J, Weinberg C.R, Baird D.D. Timing of sexual intercourse in relation to ovulation—effects on the probability of conception, survival of the pregnancy, and sex of the baby.New Engl J Med. 1995; 333: 1517-1521
  3. 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. Published 2017 May 16. doi:10.1002/btm2.10058
  4. Clubb E. Natural methods of family planning. J R Soc Health. 1986 Aug;106(4):121-6. doi: 10.1177/146642408610600402. PMID: 3091823.
  5. Kerin J. Ovulation detection in the human. Clin Reprod Fertil. 1982 Mar;1(1):27-54. PMID: 6821195.

24 thoughts on “Peak Ovulation Day [How to Maximize Your Fertility]”

    1. Brittany Robles, MD, MPH, CPT

      Hi Thara,

      Thanks for your comment!

      The LH surge precedes ovulation by 24-48 hours.

      During the surge, the LH value can be anywhere between 20-75.

      At the time of ovulation, the LH level returns to normal levels.

      Hope this helps!

  1. I had a Mirena coil removed 3 weeks ago and was told my period should return within 21 days. I haven’t had a period yet, so have been unable to work out my cycle and start using the ovulation test. After 21 days I thought I would test anyway and just see what it said, and it was ‘Peak’! 48 hours later, I tested again and it still says ‘Peak’. Is this normal?

    1. Brittany Robles, MD, MPH, CPT

      Hi Charlie,

      Thanks so much for your comment.

      So the ovulation predictor kit, or OPK for short, is solely detecting the rise in the LH hormone. Some women can actually have an elevated LH hormone for 48 hours and thus that could be the explanation for why it was still positive.

      Hope this helps!

  2. Hi , thanks for all your information . I just have a quick question as it’s really surprising le ! How come I can see high peak ( flashes smile in clear blue ) and just the day next i see clear circule which means nothing detected fir both hormones , while I was expecting to see peak or ah least stays in high for still few more days . Is it normal ? Or women can ovulate twice so high fertility happens then stop then go again with high then peak ! Thanks

    1. Brittany Robles, MD, MPH, CPT

      It’s not uncommon for the peak to only last one day. Different tests will have different levels of sensitivity for detecting the hormones as well, so they aren’t 100% accurate all the time. The most important thing is that you did get a positive result!

      1. Hello!
        Great information thank you.

        Question…I’ve been getting peak for 3 days. I will continue to test but, when should I assume ovulation will happen or has happened?

        Thank you,

        1. Brittany Robles, MD, MPH, CPT

          Hi Iris,

          Thank you for your comment.

          Once you have a peak, there is no need to continue testing. You should just start having intercourse.

          Hope this helps!

  3. hi i was wondering ive just got my got peak and me and partner are in the same sex relationship so we are using artifical insemination to get pregnant but our donor to house on the 27th , 29th of october and then hes gonna come to house on the 1st of november in the evening as he works is their any chance for us to become pregnant please help?

    1. Brittany Robles, MD, MPH, CPT

      Hi Amy,

      Thanks for your comment and sorry for the late response!

      Ideally intercourse should happen the day of the surge and the day after.

      I hope this helps and good luck with everything!

  4. Thank you for all the information!
    With a peak opk on day 18, did ovulation happened on day 19 possibly day 20? I normally have 28 day cycles, with ovulation on day 14/15, but this cycle I got a high on day 16&17 and then a peak on day 18, which is late for me. I am now on cycle day 33 with negative HPT, and no period… Should I call my OB since its not normal for me?

    Thank you

    1. Brittany Robles, MD, MPH, CPT

      Hi Ursula,

      Thank you so much for the comment.

      Ovulation occurs ~24-36 hours after the peak LH surge. If your OPK was positive on the 18th, it is possible you ovulated on the 19-20th.

      Ideally you want to check a home pregnancy test 2 weeks after you had intercourse. If the home pregnancy test is negative with no return of menses I would contact your OB and perhaps have a beta hCG level measured as this is more sensitive in early pregnancy compared to a home pregnancy test.

      Hope this helps!

  5. I noticed that my wife period is in different time. 3 October, 1 November , 6 December. Then can you suggest when is her actual ovulation time..?

    1. Brittany Robles, MD, MPH, CPT

      Hi Suraj,

      Thank you so much for your comment.

      It is completely normal for the period to occur on different days of the month.

      Unfortunately, I cannot tell you for certain the exact day ovulation is going to happen. I would recommend that your wife use ovulation predictor kits starting around day 14 of her menstrual cycle.

      Hope this helps!

  6. Hi, I’ve just got my first peak using a OPK on day 21.. is that normal? Also the night before I had the positive peak test I had right pelvic pain – is that an indication I’ve already ovulated?

    1. Brittany Robles, MD, MPH, CPT

      Getting a peak on Day 21 indicates that your cycles are on the longer side, maybe >35 days. Ovulation should occur after the peak, not before.

  7. Hello, I had a positive peak (solid smiley) yesterday afternoon day 9 of my cycle, so my husband and I had intercourse twice last night. Before that on days 7 and 8 I showed high fertility (blinking smiley). They say to have intercourse the day of and after you reach peak, but to be sure I took another ovulation test out of another box I had and it is now showing a clear circle for low fertility (day after peak). Is this normal? Does this mean I am no longer ovulating? Thanks.

    1. Brittany Robles, MD, MPH, CPT

      Hi Kaci,

      Thank you so much for your comment.

      Yes, this is normal. Once you have ovulated and seen the positive peak, you should not take another ovulation test.

      Ovulation is a one-time event.

      Hope this helps!

  8. I’m nursing, so still haven’t gotten my periods back. I’m 8 months pp, and randomly started testing with the opk kit, within a week I got a smiley face. Is this reliable ? I haven’t had a period in over a year between my last pregnancy and now breastfeeding, but want to get pregnant again.

    1. Brittany Robles, MD, MPH, CPT

      Hi Jenny,

      Thank you so much for your comment and congratulations on your baby and breastfeeding journey!

      It is possible to have random ovulations while breastfeeding but it is hard to say if it is truly reliable.

      Hope this helps!

  9. Hi there, I recently had a fimbreictomy reversal. I have been getting a blinking smiley face for 4 days. Is it possible I may not ovulate at all?

    1. Brittany Robles, MD, MPH, CPT

      Hi Rachel, It’s possible that your hormones are going up at a slower rate than usual. Keep checking it daily. You may also have to repeat next month and see if it happens again to confirm.

  10. Good day, my wife had a menstrual cycle on 20th December 2021 while again on 19th January 2022. How do I calculate her ovulation day at the moment.
    Thanks in anticipation Sir.

    1. Brittany Robles, MD, MPH, CPT

      Hi Ebhoma,

      Thank you so much for your comment.

      If your wife typically has regular, 30-day cycles, she should start checking ovulation predictor kits (which can be bought over the counter) on days 12-14. (Day 1 is the first day she starts bleeding). This will help you determine when she will ovulate.

      Hope this helps!

      he has regular periods 30 day cycles
      start checking OPKs on day

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