Knowing when you ovulate is one of the most important things that can help you get pregnant. You can only get pregnant when sperm encounter a fertile egg, so if you don’t know when that egg will be released you won’t know when you’re fertile.

Today we’re taking a look at these issues, so you can choose the best ovulation tracker for you.

Ovulation and Fertility

While it’s important to know when you ovulate, this date doesn’t mark when you become fertile. Sperm need to encounter that egg in order to fertilise it, and they can survive a relatively long time in the uterus and fallopian tubes. On average, sperm survive around five days inside your body, so your ‘fertile window’ begins five days before you ovulate.

This should make it clear that it’s more useful for you to predict when you ovulate, so you can use more of those fertile days to try and get pregnant. Look out for the predictive power of each ovulation tracking option, not just how they can confirm if you’re ovulating on a given day.

Ovulation Predictor Kits

These tests, also known as OPKs work very similarly to pregnancy tests. Each test is a one-use stick that you dip into your urine – either directly into the flow or by collecting it in a pot. For some tests, the results are displayed directly on the stick, with a line that appears or a colour that changes in response to the high level of Luteinising Hormone that the test is looking for.

Some more advanced OPKs come with a second component that you need to plug the test stick into which can give you a more nuanced, and easy to interpret response. Some of these more complex tests may cost more, but they can also track your hormone levels over time, allowing them to learn what’s normal for your body and alert you further in advance of when you ovulate.


There are some drawbacks to using these tests.

Most OPKs offer very little predictive power, telling you if you’re ovulating on a given day, but not far enough in advance for you to have access to your full fertile window. It’s also possible that you could miss a notification that you’re ovulating if you simply take the test at the wrong time on ovulation day! Even among experts there is little agreement over the best time of day to take the test for a more accurate result, which makes it hard to feel confident you’re getting the information you need!

You can also get false positives, or a negative result when you are ovulating if your LH level is higher or lower than average. Health conditions or medication side effects can lead to hormone disruptions like this, but it can also simply be a natural feature of your body. This makes it hard to recommend OPK tracking for people whose hormones could be in anyway affected or different from the average the tests are calibrated for.