When to Take an Ovulation Test?


If you’re trying to get pregnant, it’s important to understand when you might be ovulating, as the “fertile window” is when you have the greatest chance of conception.

During reproductive ages, the ovary releases an egg every month. The process of ovulation is controlled by the hypothalamus of the brain and through the release of hormones. This means that ovulation can be impacted by hormone levels and stressors.

After the oocyte is released from the ovary, it moves into the fallopian tube. At this point it is called an ovum or egg. The egg stays in the fallopian tube for about 24 hours, waiting for a single sperm to fertilize it.

If the egg is not fertilized by sperm during that time (and pregnancy does not occur), it disintegrates (breaks down) and menstruation (your menstrual period) begins 11-16 days later.

Ovulation tests can be a useful tool for those trying to conceive and wishing to identify the best time to try to get pregnant.

Ovulation and Pregnancy: The Fertile Window

For many, ovulating is an unnoticed process. However, for those hoping to get pregnant, knowing when you might be ovulating is important. This starts with understanding your cycle length.

Your most fertile days ("the fertile window") are the 3 days leading up to and including ovulation. This is when  getting pregnant is most likely. So, having sex then gives you the best chance of ensuring the egg is fertilized by sperm so you become pregnant.

But, as previously mentioned, ovulation is a delicate process. Not to mention, the woman's reproductive cycle is just one side of the equation. Sperm heath is also key in your chances of getting pregnant.

As most women will attest, cycle length can be impacted by stress, exhaustion or emotional events (like grief). Moreover, nutrition, smoking and seasonal changes can also impact ovulation and therefore fertility.

When to Take an Ovulation Test

Based on your own individual cycle, you should start testing with an ovulation kit 3 days before your expected ovulation day.

Ovulation tests identify the LH surge (luteinizing hormone) 24-36 hours before ovulation. It’s important to factor in that sperm can survive in a woman’s body up to 5 days, so if you have sex before you ovulate, there can still be sperm present to fertilize the egg.

Every woman’s cycle is different. Some of us have longer periods than others, for example. So the timing of ovulation and of taking an ovulation test is not always the same in every woman's cycle.

But generally a woman’s entire cycle is on average 28 days. That said, it can range between 21 to 35 days in adults and from 21 to 45 days in young teenagers. That's why most women track their own cycle with a periods calculator or diary.

The first day of a cycle is counted from the first day of your menstrual period. You ovulate about 14 days before your period starts.

So, if your average cycle is 28 days and the first day of your cycle is Day 1 of your menstrual period, day 14 in your cycle is your day of ovulation, and your most fertile days are days 12, 13 and 14. These are the days pregnancy is most likely to occur and when you should start testing with an ovulation test.

And if your average cycle is 35 days ovulation happens around day 21 and your most fertile days are days 19, 20 and 21 and these are the days when you should start testing with an ovulation test.

What If Your Cycle is Irregular?

If your menstrual cycle is irregular it might be much more difficult to pinpoint the date of ovulation and to understand when to take an ovulation test. Even with a regular cycle, the day of ovulation can move around.

This makes it challenging to narrow the right day to use an Ovulation Predictor Kit and can add expense to the process. 

If you keep a period diary, it’s worth going by your shortest cycle in the last 6 months as an indication of when you’re likely to ovulate on your current cycle. It’s worth noting that even on an irregular cycle, the luteal phase is fairly stable and lasts about 14 days. Learn more about the phases of your menstrual cycle here.

You can also look out for the other symptoms of menopause (see last section), especially a change in your cervical mucus. According to the American Pregnancy Association “it is best to wait until you start to notice a build-up of fertile-quality cervical mucus before you begin testing”.

It is best to read the instructions and information on your ovulation test closely and follow individual brand instructions.

Are Ovulation Tests Accurate?

Ovulation kits are 99% accurate at predicting the increase in luteinizing hormone (LH surge) that precedes ovulation. However, they cannot confirm that ovulation has occurred, or when.

There are a few other reasons your body might indicate a LH surge (luteinizing hormone) that is not accompanied by you ovulating. These include:

  • Luteinized Unruptured Follicle Syndrome (LUFS): This is a surge in LH without the release of an egg.
  • Polycystic Ovarian Syndrome (PCOS): According to the Mayo Clinic, “women with PCOS may have infrequent or prolonged menstrual periods or excess male hormone (androgen) levels. The ovaries may develop numerous small collections of fluid (follicles) and fail to regularly release eggs.”
  • Pregnancy: If you're already pregnant, you may register a positive ovulation test but not necessarily be ovulating. If you suspect you're pregnant, take a pregnancy test.

Other Signs & Symptoms of Ovulation

Ovulation usually goes unnoticed in many but there are some ovulation symptoms that most women can learn to track or pay attention to to help understand when to take ovulation tests:

Your Basal Body Temperature Falls

One of the most objective ovulation symptoms is that your basal body temperature drops a little bit just before your egg is released from your ovary. Then, 24 hours after the egg is released, your basal body temperature rises and stays up for several days. If you're trying to get pregnant, it's advisable to take your temperature to understand when you're ovulating.

Discharge Changes When You Ovulate

The changes in your cervical mucus over the course of your cycle also hold clues about when you might be ovulating.

If your cervical mucus is...

  • Dry or sticky: It’s unlikely you’re ovulating
  • Creamy cervical mucus: Ovulation may be coming
  • Wet or watery: Ovulation may start soon
  • Wet and stretchy (egg white texture): You may be at your day of ovulation

Your Cervix Softens and Opens Up

As you approach your most fertile time, your cervix softens. This is sometimes known as having a short, high, open and wet cervix. 

You May Experience Slight Twinge or Cramping

Mittelschmerz translates literally as “middle pain” and is the name for the slight twinge or cramp that some women experience when the follicle releases the egg on the day of ovulation during your menstrual cycle.

Some Light Spotting May Occur When You Ovulate

When the ovaries release the egg, a tiny follicle ruptures to allow the egg to be released. This can be a cause of spotting for a day or so.

Increased Libido or Sex Drive

The most well-known sign of ovulation is an increased sex drive. 


Ovulation tests are a useful tool for women hoping to get pregnant. However, it’s also worth tracking other signs and symptoms of your menstrual cycle and understanding each stage. 

If you are trying to conceive, having a holistic understanding of your entire cycle and using ovulation tests will help you zero in on the best time to take the test and increase your chances of becoming pregnant.

If you think you might be pregnant, take a pregnancy test.