Ovulation Calculator: The Most Fertile Days In Your Menstrual Cycle

Ovulation Calculator: Find Out The Most Fertile Days In Your Menstrual Cycle

April 27, 2020 Updated June 28, 2021

ovulation calculator
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Trying to get pregnant? You’ve come to the right place. Well, we can at least help point you in the right direction — the baby-making itself is obviously an extracurricular activity for the bedroom (or the car, or the kitchen counter or, you know, wherever). But we digress. The most fertile days of your menstrual cycle occur around the time you’re ovulating. According to the American Pregnancy Association, this is known as your “Estimated Fertility Window.” And the quickest way to pinpoint that window is by using an ovulation calculator.

As luck would have it, we just so happen to have one of those to aid in your baby-making math. So, before we dive into the science, pop your details into our ovulation calculator and, based on the info you provide, we’ll help you nail down which dates in your next cycle have an increased likelihood of getting you knocked up.

Ovulation Calculator
First Day of Your Last Period
Cycle Length

Why is this the best time to get pregnant?

We’re gonna let you in on a little secret no one told us when we were new to the whole baby-making thing — you’ll see the initials “TTC” everywhere. You’ll see it on message boards. You’ll see it in articles. You’ll start to see it in your sleep, even. It means “trying to conceive.” And if you are, in fact, joining the TTC universe, you obviously want to know everything you can about the process. The one that happens after sex or insemination, that is — you’re probably up-to-speed on the birds and the bees by now.

For conception to take place, you need at least one sperm hanging out in the fallopian tube during ovulation. This spirited little swimmer must be able to fertilize the egg within 12 to 24 hours of the egg being released from the ovary. Sperm can only survive a maximum of five days in the female reproductive tract, meaning very few even live long enough to make it to the egg.

So, to increase the odds, you’ll want to take advantage of every opportunity in the days leading up to ovulation. This also means having sex on one of the days leading up to ovulation can still result in pregnancy. Of course, this means you need to actually know when you’re ovulating.

How to calculate your average menstrual cycle length?

With an endless stream of period tracker apps available at your fingertips, it’s easy to just let the app do all the math for you. And that’s totally fine and in fact smart to have a written log of your cycle somewhere at easy reach. That said, it’s still good to know the math behind the app’s calculation, especially since it’s so easy.

You can calculate your cycle by counting from the first day of your period to the day before the next first day. So, say you got your period on March 1, and the next first day was March 31. That means your cycle lasted from March 1 to March 30, coming to a 30-day cycle. Since our cycles can fluctuate month to month, it’s best to take an average of three months’ worth of data to get a more accurate snapshot of your cycle length.

How can you tell if you’re ovulating?

Our ovulation calculator will give you a general guide to help you track your ovulation. Ovulation kits (which detect the presence of luteinizing hormone in urine), ovulation microscopes (which observe visual changes to saliva brought on my estrogen), and electronic fertility monitors (which use oral and vaginal sensors to track ovulation) are also popular choices for predicting the estimated fertility window.

You can also pay attention to common physical and physiological symptoms such as changes in cervical fluid, basal body temperature, and changes in cervical position or firmness. During ovulation, cervical mucous is stretchy, milky-white, and opaque. The texture and pH of mucous during this time of the month actually serves as a protective environment for sperm. Possible secondary signs include light spotting, slight cramping, breast tenderness, abdominal bloating, increased sex drive, and heightened senses.

If you suspect you may be pregnant, a checklist of early pregnancy symptoms and a pregnancy test can help confirm your suspicions. In which case, congrats! Did you know you don’t have to wait until your first OB appointment to find out your due date? By entering your conception date or the first day of your last period into Scary Mommy’s due date calculator, you can lock down when your little one will make their big appearance.

Is it possible you’re not ovulating?

If you’re TTC, you’ve probably read about all the symptoms to track and monitor to spot ovulation. Signs like a higher basal body temperature, egg white-like cervical mucous, bloat, and even increased sexual libido. This type of cervical fluid may also be released even if a woman is not ovulating, which is where ovulation test kits come in. You may also be using ovulation test kits and they might not be showing ovulation days at all.

Most important, don’t panic. There are many reasons why you might not be ovulating, some of them include (but are not limited to):

1. Being under stress
2. Being significantly over- or under-weight
3. Poor nutrition
4. Excessive exercise (hours a day every day)
5. Hormonal irregularities
6. Breastfeeding/nursing
7. Thyroid dysfunction
8. Polycystic Ovarian Syndrome (PCOS)
9. Perimenopause or ovarian failure
10. And other reasons

You should schedule an appointment with your gynecologist and bring this up. They’ll be able to conduct tests to pinpoint what the root cause of this might be.

What if my cycles are shorter than 21 days or longer than 35 days?

The length of a menstrual cycle varies from woman to woman, and no two cycles are the same. You should consult with your gynecologist if you’re experiencing irregular menstrual cycles — that is, cycles that are shorter than 21 days or longer than 35 days, missing periods for three or more months in a row, your periods are heavier or lighter than usual, or your periods last longer than seven days. Other symptoms may also include severe cramping, nausea, or vomiting.

Am I most fertile before or during ovulation?

This is kind of a trick question. You are most fertile during ovulation, as the egg has been released and is primed for conception if a suitable suitor, aka a sperm cell, fertilizes it. But conception can still occur if you have sex up to five days before ovulation. That said, a woman is most fertile and has a higher chance of conceiving if she is intimate three days before ovulation and during ovulation.

If you are tracking your ovulation to avoid pregnancy, it is best to eschew unprotected sex during your most fertile days. Tack on an additional two days before ovulation for extra protection as sperm can survive up to five days in the cervix.

How many days after ovulation can you get pregnant?

Just because you’re not ovulating doesn’t mean you’re completely out of the woods. A person can get pregnant up to 12 to 24 hours after ovulation. This is because an egg can survive up to 24 hours in the cervix. Now, if you’re asking, “Can I get pregnant 10 days before my period?” Well, it’s not out of the realm of possibility! Of course, it varies due to a variety of factors, including primarily when you ovulate and whether your cycle is regular. However, since ovulation typically occurs in the middle of your menstrual cycle — or about two weeks before your menstrual cycle — it’s possible (and perhaps even likely) that you could get pregnant 10 days before your period.

What are the earliest signs of pregnancy?

So, you’ve been TTC and tracking your ovulation in hopes that it will happen. What that also means, of course, is that every month you’ll be waiting with bated breath to find out if your baby-making efforts were successful. Which also means you’re going to be scrutinizing every little thing that happens with your body, wondering if it might be an early sign of pregnancy. Possible early signs of pregnancy include a missed period, nausea, tender breasts, extreme fatigue, headaches, and slight bleeding or cramping (known as implantation bleeding).