The Best Ovulation Tracker Apps to Identify Your Fertile Window

When you're trying to become pregnant or hoping to avoid it sans hormones, simply winging it probably won't get you the results you're hoping for.

But adding an ovulation tracker app into your personal reproductive health-care toolkit could help you get the job done. These apps record your menstrual cycle dates and, in some cases, basal body temperature (your at-rest temp) and other bodily changes (i.e. cervical mucus and position) to estimate when you'll ovulate each month. Reminder: Ovulation is the point in your menstrual cycle when a mature egg is released from the ovaries, and it generally occurs 14 days before the first day of your period, says Lauren Bishop, M.D., a reproductive endocrinologist at Columbia University Fertility Center. "So if you're having a regular 28-day cycle, then you're ovulating on day 14 of the cycle," she explains. Even if you have an irregular cycle, your period will always occur about two weeks after ovulation, she adds.

Your basal body temperature can also clue you in on when you're ovulating. Just before your ovary releases an egg, your temperature dips slightly (between 97°F and 97.5°F, on average), then it rises 24 hours after release and stays high for several days (roughly between 97.6°F and 98.6°F), according to University of Michigan Health. By logging your basal body temperature every morning before getting out of bed — which you can do on some ovulation tracker apps — you'll slowly get an idea of when you're ovulating and predict when it'll next occur, according to U of M Health. (

Similarly, your cervix — the opening to the uterus — can show signs of ovulation. During ovulation, your cervix sits high in the vaginal canal and has a soft texture, and it's low in the canal and firm beforehand, according to research. This tissue also produces and releases a fluid, called cervical mucus, that changes in texture, volume, and color throughout your menstrual cycle due to hormones, according to the Cleveland Clinic. In the days leading up to ovulation, your mucus is thick, white, and dry, but it turns clear and slippery right before you release an egg.

After the egg is released, it moves into the fallopian tube and settles there for 12 to 24 hours, during which time it can be fertilized, according to the Mayo Clinic. Since sperm can survive in the reproductive tract for up to five days after intercourse, there are about six days each menstrual cycle that you can get pregnant (the five days leading up to ovulation and ovulation day), a period known as your fertile window, according to the U.S. Department of Health and Human Services' Office on Women's Health.

Why Use Ovulation Tracker Apps, Anyway?

One of the biggest perks of using ovulation tracker apps and other tools? Knowing when your fertile window occurs can help you time sex to increase your chance of getting pregnant, according to the OWH.

The opposite holds true, too: Ovulation tracker apps can be useful for folks looking to minimize the likelihood of pregnancy, says Dr. Bishop. "If you're trying not to get pregnant, then you know when your most fertile time is and so you should avoid having intercourse around then," she explains. "Obviously, this is not a fail-safe method, but…you know when to at least not be having intercourse." Specifically, tracking ovulation contraception is effective only about 76 percent of the time, according to the Cleveland Clinic, so you'll likely want to use a second type of birth control (i.e. condoms, Phexxi) to further reduce your odds of pregnancy. (

Regardless of why you're using an ovulation tracker app, don't always take the information at face value. "If what the app is telling you doesn't correlate to that 14-day time window [for ovulation], then maybe you should think about the accuracy of the app," says Dr. Bishop. Make sure that those two things are lining up."

You can also double-check its accuracy by using it alongside ovulation prediction kits, which test your urine for luteinizing hormone — a hormone that rises when the ovary releases an egg, says Dr. Bishop. Generally, you'll start testing three to five days before you expect to ovulate, and if you get a positive result (meaning a surge in luteinizing hormone is detected), you should ovulate within the next 24 to 36 hours, according to the National Library of Medicine. "If your test strips are saying that you're ovulating, but your app is saying you're ovulating three days later, then the urine strips would be more accurate," says Dr. Bishop. In that instance, you may want to consider switching apps. (BTW, these period tracker apps will help you predict your monthly flow.)

How Long Should You Use an Ovulation Tracker App?

Since your cycle's length may change from month to month, Planned Parenthood recommends tracking your ovulation day and period for at least six cycles to get a better idea of when your fertile window typically occurs. The longer you keep track of it, the more likely you'll be able to see a pattern, leading to more accurate predictions, according to the Cleveland Clinic.

That said, it may be tough to estimate when you're ovulating if you have an irregular period, says Dr. Bishop. "[For] women who, for instance, have PCOS and only get a period every three months, it's often challenging for them to achieve a pregnancy because they're ovulating very erratically, and so they don't know when to time intercourse," she explains. If you're struggling to conceive by relying primarily on an ovulation tracker app or tool, "it would be better to reach out to your ob-gyn or reproductive endocrinologist to talk about different treatment options or way to track and improve your chances of pregnancy," suggests Dr. Bishop.

7 Ovulation Tracker Apps to Download

Best Ovulation Tracker App to Use Through Pregnancy: Flo Period & Ovulation Tracker

Boasting more than 800,000 reviews in the App Store, Flo's Period and Ovulation Tracker app is sure to give you all the fertility insights you're after. The app records your period and cycle length, then uses that data to predict your ovulation day and fertile window, as well as compute your chance of getting pregnant each day. All of this data is saved in a Cycle History section, so you can see how your menstrual cycle has changed over time and if you're experiencing any irregularities in it. If you do become pregnant, turn on Flo's pregnancy mode to see images of your baby's weekly growth, calculate a due date, and set a countdown to your newborn's arrival.

Available in the App Store and on Google Play.

Best Ovulation Tracker App for All Ovary Owners: Clue Period & Cycle Tracker

By ditching the traditional pink color scheme and gendered language, Clue's ovulation tracker app is sure to be a comfortable, inclusive fertility-tracking space for all users. The app can log your period, keep a record of your basal body temperature, ovulation tests, and cervical fluid, and use this info to predict your cycle length and ovulation day. To ensure you never miss a fertile window, you can also set up a reminder that your ovulation day is approaching, as well as nudges to take your temperature or birth control. (Wait, what should you do if you miss a birth control pill?)

Available in the App Store and on Google Play.

Best Ovulation Tracker App with High-Tech Features: Modern Fertility

Whether you're trying for kids or desperately want to avoid them, Modern Fertility's ovulation tracker app can help you get the job done. The app allows you to track your periods and predicts the two days you're most likely to get pregnant during your menstrual cycle. To improve the accuracy of your estimated ovulation days, you can also input your luteinizing hormone levelsand use the built-in scanner to log your results from a Modern Fertility ovulation test — no typing required. And if you are gunning for a baby, the app will suggest the best days to take a pregnancy test. (FTR, these tests are most accurate after you've missed your period, according to Planned Parenthood.)

Available in the App Store.

The Best Paid Ovulation Tracker App: Natural Cycles

You'll have to shell out $10each month for this ovulation tracker app, but it's well worth the price tag: Natural Cycles is the only birth control app cleared by the U.S. Food and Drug Administration and it is 93 percent accurate with typical use, per the FDA. To give you accurate results, the app requires you to take and log your temperature using a basal body thermometer immediately after waking up daily. Then, it uses this data — combined with info about your period and cycle length — to predict ovulation and your fertile window. If you're fertile, the day on the app's calendar will turn red and tell you to use protection (if you're trying to avoid pregnancy) and it will turn green on days you're not fertile.

Available in the App Store and on Google Play.

Best Ovulation Tracker App for Expert Insight: Ovia Fertility & Cycle Tracker

Instead of frantically Googling all of your fertility Qs, turn to Ovia. Within the app, you'll have access to more than 2,000 free articles on fertility, conception, and reproductive health straight from the pros. Of course, the ovulation tracker app allows you to log your period and cycle length, as well as your basal body temperature, cervical fluid, medications, and other data that may clue you in on your fertility. Plus, the app tells you exactly how many days you are into your cycle and fertile window and gives you a daily "fertility score" so you'll have an idea of your best days to try for a baby.

Available in the App Store and on Google Play.

Best Ovulation Tracker App for Data: Kindara Fertility Tracker

If you'd rather skip the frills and get clear-cut data, download Kindara, an ovulation tracker app that allows you to record your period, basal body temperature, cervical mucus and position, ovulation and pregnancy test results, sexual intercourse, PMS symptoms, and more. For each metric, the app provides detailed charts and graphs showing how they've changed over time — all of which you can easily share with your healthcare provider. Plus, the included digital calendar makes it a breeze to find out when to expect your next fertile window.

Available in the App Store and on Google Play.

Best Ovulation Tracker App for Couples: Glow Fertility & Ovulation App

Thanks to Glow's partner-sharing capabilities, you can keep your S.O. up-to-date on your fertility journey — if you want. Adding your partner to the app allows them to see stats such as key menstrual cycle dates, logged basal body temperature and cervical mucus description, chances of pregnancy, and more. If you haven't added your information for the day, your partner can ping your a reminder to do so. (Next Up: The Best Therapy and Mental Health Apps)

Available in the App Store and on Google Play.