Natural Cycles vs Flo vs Clue: Which Cycle Tracking App Is Best?
Tech
Key Findings
Natural Cycles is best for FDA-cleared, hormone-free contraception, Flo is the strongest all-round option for periods, fertility, and pregnancy, and Clue is better for detailed symptom tracking and cycle analysis. Flo and Clue both offer free versions, while Natural Cycles requires a subscription.
Natural Cycles, Flo and Clue are often grouped as cycle-tracking apps, but they are all built for different purposes.
Natural Cycles is a regulated contraceptive app that uses body-temperature data to determine daily fertility status.
Flo provides broader reproductive-health support across periods, fertility, pregnancy and perimenopause, while Clue puts more emphasis on detailed tracking, cycle patterns and data visualization.
That difference matters when choosing between the best cycle tracking apps.
Someone who mainly wants to know when their next period is likely to arrive has very different needs from someone looking for hormone-free birth control or someone who wants to compare cramps, mood, sleep and other symptoms across several months.
Why Use a Cycle Tracking App?
A cycle tracker can turn scattered dates and symptoms into a clearer view of what tends to happen throughout the month.
Regular menstrual cycle tracking may help you anticipate periods, notice recurring symptoms, and understand whether certain experiences tend to appear at similar points in your cycle.
Benefits of Using a Cycle Tracking App
Predict upcoming periods: Logging period dates over time can help an app estimate when your next period may begin, which can be useful when planning travel, workouts, or everyday routines.
Identify symptom patterns: Recording cramps, mood, energy, sleep, skin, appetite and other experiences can make it easier to spot symptoms that repeatedly show up during a particular part of your cycle.
Understand fertility: Some apps estimate fertile windows to support conception planning. These predictions should not be treated as contraception unless the app is specifically cleared and intended for that purpose.
Follow different life stages: Apps with multiple modes can remain useful when your needs shift from period tracking to conception, pregnancy, postpartum, or perimenopause.
Communicate more clearly: Cycle histories, reports, and partner-sharing tools can help you explain patterns to a healthcare professional or keep a partner informed.
Natural Cycles vs Flo vs Clue: Comparison at a Glance
The biggest difference is what each app is designed to do, with Natural Cycles focused on contraception, Flo on broad reproductive-health support, and Clue on detailed cycle analysis.
Comparison | Natural Cycles | Flo | Clue |
Best For | Hormone-free birth control and fertility tracking | All-round cycle and pregnancy support | Detailed symptom and pattern tracking |
Price | $21.99/month or $149.99/year | Free; Premium prices vary, with US plans up to $59.99/year | Free; Plus costs $9.99/month or $39.99/year |
USP | FDA-cleared birth control using temperature data | Broad reproductive-health support across different life stages | Science-led analysis with highly customizable tracking |
Key Features | Daily fertility status, ovulation confirmation, pregnancy, postpartum and perimenopause modes | Period predictions, symptom insights, fertility, pregnancy and perimenopause | Cycle predictions, 200+ tracking options with Plus, Conceive, pregnancy and perimenopause |
Free Version | No | Yes | Yes |
Birth Control | Yes; 93% effective with typical use | No | No |
Wearable Support | NC° Band, Oura, supported Apple Watch models and compatible Garmin devices | Apple Watch and Apple Health | Oura, WHOOP, Apple Watch, Fitbit, Withings and several others |
Natural Cycles Review
Natural Cycles differs from a standard period tracker because its main purpose is not simply to estimate when your next period or fertile window may occur. It is an FDA-cleared birth control app.
Its algorithm analyzes body-temperature data and other cycle information to give you a daily fertility status: Green Days when the app says you are not fertile and Red Days when protection or abstinence is required if you are preventing pregnancy.
Temperature is central to how the app works. You can measure with a compatible basal thermometer or use supported overnight wearables, including the NC° Band, Oura Ring, compatible Apple Watches and certain Garmin devices.
Wearables can make the routine easier because they collect temperature while you sleep, while thermometer users need to follow Natural Cycles' morning measuring instructions consistently.
The Natural Cycles app price is higher than what you would pay for a basic period tracker at $21.99 per month or $149.99 per year.
That may make sense if you plan to use its regulated birth control mode, but it is harder to justify if you only want basic period predictions.
A subscription also includes modes for planning pregnancy, following pregnancy, postpartum recovery, and perimenopause.
Natural Cycles Key Features
FDA-cleared hormone-free birth control: Natural Cycles is specifically intended to be used as contraception in supported markets, making it fundamentally different from Flo and Clue.
Daily Green Day and Red Day fertility status: The app turns its fertility assessment into a simple daily status. Green means the day has been identified as non-fertile, while Red means protection or abstinence is needed if avoiding pregnancy.
Basal-temperature and wearable-based tracking: Users can measure manually with a compatible thermometer or sync temperature from supported wearables.
Pregnancy planning, pregnancy and postpartum modes: You can change your goal without leaving the app, while postpartum mode adds recovery check-ins and information about the return of fertility.
Perimenopause support and Partner View: Natural Cycles also supports perimenopause, while Partner View lets users share fertility status, predictions and selected information with a partner.
Who Is Natural Cycles For?
Natural Cycles is best suited to adults who want a regulated, hormone-free contraceptive method and are comfortable following the app's instructions consistently.
It can also work well for people who want temperature-based fertility tracking while trying to conceive.
It does not protect against sexually transmitted infections, and no contraceptive method is completely effective. Natural Cycles states that its birth control method is 93% effective with typical use.
Verdict
Natural Cycles is the best option for regulated hormone-free contraception and temperature-based fertility tracking.
Flo Review
Flo offers the broadest general reproductive-health experience of the three. It covers period and ovulation predictions, symptom logging, trying to conceive, pregnancy and perimenopause, with a large library of expert-reviewed educational content built into the experience.
The app is designed to feel approachable even if you do not want to spend much time analyzing charts.
Flo can surface information based on your cycle day and logged symptoms, while its Health Assistant provides educational conversations around cycle changes, mood, cramps, and other topics.
Partner features can share selected cycle or pregnancy information, and Anonymous Mode gives users an additional privacy-focused way to use the app.
Flo's free plan is useful for straightforward period and symptom tracking, giving it an advantage over Natural Cycles for casual use.
Premium adds deeper content and insights, although pricing can vary by subscription and offer.
Flo can estimate ovulation and fertile windows, but these predictions should not be used as a form of birth control.
Flo Key Features
Period and ovulation predictions: Flo estimates upcoming periods and fertile windows using the cycle information you log.
Cycle and symptom-pattern analysis: Users can record symptoms and events, then review their cycle history, trends, and recurring patterns over time.
Trying-to-conceive and pregnancy modes: Flo adjusts its experience based on your goal, with fertility-focused guidance when trying to conceive and support throughout pregnancy.
Perimenopause guidance: The app also supports users navigating changes associated with perimenopause.
Flo Health Assistant, Partner features and Anonymous Mode: These tools add education, optional sharing and an extra privacy-focused way to use the app.
Who Is Flo For?
Flo is a good fit if you want one accessible app that can follow you through several reproductive stages.
It is particularly useful for people who value educational content, pregnancy support, and an easy free tracking experience without needing highly detailed charts.
Verdict
Flo is the best all-round cycle and reproductive-health app of the three.
Clue Review
Clue takes a more data-focused approach. Instead of centering the experience on a large stream of lifestyle guidance, it encourages you to record cycle-related experiences and then review how they change over time.
With Clue Plus, there are more than 200 tracking options covering bleeding, symptoms, sleep, exercise, sex, and other factors.
The Clue app interface keeps the focus on your cycle data, with calendar and analysis views designed to make patterns easier to compare across previous cycles.
The Clue app symptom tracking screen is organized into categories such as period, pain, and feelings, so you can log several experiences without creating separate notes for everything.
Clue also has dedicated modes for conception, pregnancy, and perimenopause. Clue Conceive is designed to predict fertile days as an aid to getting pregnant, but Clue is not intended for contraception.
Clue Plus also supports a wide range of wearables, including Oura, Apple Watch, WHOOP, Fitbit and Withings, allowing sleep, temperature and heart-rate-related data to be viewed alongside cycle information.
Clue Key Features
Detailed period and cycle predictions: The Clue app period tracker estimates upcoming periods based on your logged history, while paid users can access longer-range predictions.
More than 200 trackable symptoms and experiences: Clue Plus offers extensive tracking categories, allowing users to build a much more detailed record than a simple period calendar.
Clue Conceive fertility predictions: Conceive mode is designed for people trying to get pregnant and provides personalized fertile-day estimates.
Advanced charts, analysis and Cycle Report: The Analysis tab can show period flow, cramps, basal body temperature and complete cycle overviews. Clue also offers a downloadable report designed for sharing recent cycle data and symptom trends with a healthcare provider.
Clue Connect and broad wearable support: Clue Connect can share basic cycle information with someone you trust, while wearable integrations bring additional health data into the app.
Who Is Clue For?
Clue is best for people who like recording detailed information and looking for patterns across multiple cycles.
It is particularly useful if you would rather explore charts and tracked data than work through a large amount of lifestyle content.
Verdict
Clue is the best option for detailed, science-led cycle and symptom tracking.
So, Which Is the Best Cycle Tracking App in 2026?
The best app depends on what you actually want to track.
Natural Cycles is the strongest choice if your main goal is FDA-cleared, hormone-free contraception. It uses temperature data to determine daily fertility status, but it also costs more than Flo or Clue and requires more consistent input.
Flo is the best all-round option for most users. It covers period tracking, fertility, pregnancy and perimenopause, with a useful free version and plenty of educational content. It is a good fit if you want one app that can support you through several reproductive stages.
Clue is better suited to people who want more detailed tracking and analysis. Its large number of tracking options, charts, and cycle reports make it easier to compare symptoms and patterns over time.
Flo and Clue both offer free versions, while Natural Cycles requires a subscription.
If you mainly want period predictions and symptom tracking, Flo or Clue will likely be enough.
If you specifically want to use an app for birth control, Natural Cycles is the only one of the three designed for that purpose.
Alternative Cycle Tracking Apps
Natural Cycles, Flo and Clue cover many common needs, but there are other options worth considering if you want broader health context, built-in Apple integration or a stronger fertility focus.
Neura Health
Neura is not a contraceptive app, but it does offer menstrual cycle tracking alongside its broader health features.
It can pull in existing cycle history from connected health apps, show where you are in your cycle, compare recent cycles, and track factors such as period length, cycle length, symptoms, and fertile-window estimates.
Where Neura differs is that it connects your cycle with other health data.
For example, it may show that your sleep tends to get lighter or your cravings and stress increase during a certain phase of your cycle.
You can then use that information to adjust workouts, recovery, or other daily habits around patterns you regularly experience.
Apple Cycle Tracking
Apple Cycle Tracking is a convenient free option for iPhone and Apple Watch users.
You can log your period, symptoms, and other cycle information directly through the Health app, with predictions for upcoming periods and fertile windows based on the information you record.
Compatible Apple Watch models can also use wrist-temperature data to improve period predictions and provide retrospective estimates of when ovulation may have occurred.
Because everything sits within Apple Health, it can be particularly convenient if you already use an Apple Watch for sleep, activity and other health tracking.
Stardust
Stardust is a period tracker with a more visual and personality-driven experience than Natural Cycles, Flo or Clue.
It offers cycle predictions, symptom logging, and partner-sharing tools for people who want a simple way to keep someone else informed about where they are in their cycle.
Privacy has also been a significant part of Stardust's branding. However, users who prioritize privacy should still review the company's latest privacy disclosures and app permissions before deciding whether it fits their preferences.
Premom
Premom is a stronger option for people who are actively trying to conceive.
The app can combine period history, ovulation test results, basal body temperature, and other fertility markers to help users identify their fertile window.
It is particularly useful if you already use ovulation test strips because you can keep those results alongside the rest of your fertility information rather than tracking everything separately.
Ovia Fertility
Ovia Fertility is designed around fertility and conception planning while still offering everyday cycle and symptom tracking.
It includes fertile-window estimates, ovulation predictions, and a daily fertility score based on the information you log.
You can also record symptoms, moods, and other health information, and the broader Ovia platform extends into pregnancy and postpartum support.
It is worth considering if you are trying to conceive and want a free app that can continue to be useful if you become pregnant.
Final Thoughts: Natural Cycles vs Flo vs Clue
Natural Cycles, Flo, and Clue should not really be treated as interchangeable apps.
Natural Cycles makes the most sense for someone seeking regulated hormone-free contraception, Flo is the strongest all-round option for cycle tracking and reproductive-health support, and Clue is better suited to people who want detailed records, charts and symptom analysis.
The right choice ultimately depends on what you want to track and how much information you want from the app.
Cycle predictions can be useful for understanding your own patterns, but unexpected symptoms, persistent irregularities, or fertility concerns are worth discussing with a qualified healthcare professional.
Article FAQ
How accurate is the Flo app for ovulation?
Flo can give a useful estimate of when ovulation may happen based on your cycle history and the data you log, but it cannot confirm the exact day. Ovulation can shift because of stress, illness, travel, or other changes. Flo’s fertile-window predictions are best used for cycle awareness rather than birth control.
How many symptoms does the Clue app track?
Clue Plus offers more than 200 tracking options covering symptoms, cycle experiences, and lifestyle factors. These include cramps, headaches, bloating, mood, bleeding, sleep, exercise, and sexual activity. You can customize what you track and use Clue’s charts and analysis tools to compare symptoms across cycles and look for recurring patterns.
How much does the Natural Cycles app cost?
Natural Cycles costs $21.99 per month or $149.99 per year through the US Apple App Store. Unlike Flo and Clue, it does not offer a standard free version. The subscription includes its fertility algorithm, daily Green Day and Red Day status, and additional modes for pregnancy planning and other reproductive stages. Pricing can vary by region or promotion.
What is the best cycle tracking app?
The best cycle tracking app depends on what you need. Natural Cycles is best for FDA-cleared, hormone-free contraception, Flo is a strong all-round choice for periods, fertility, and pregnancy, and Clue is better for detailed symptom tracking and cycle analysis. Flo and Clue also offer free versions for basic tracking.
Can Flo or Clue be used as birth control?
No. Flo and Clue can estimate ovulation and fertile windows, but neither app is intended to be used as contraception. Their predictions are better suited to cycle awareness or conception planning. Natural Cycles is different because it is FDA-cleared in the US as a digital birth control method.
Is Natural Cycles FDA-cleared?
Yes. Natural Cycles is FDA-cleared in the US as a digital birth control method. It uses temperature and cycle data to identify fertile and non-fertile days and gives users daily Green Day or Red Day guidance. Natural Cycles reports 93% effectiveness with typical use and 98% with perfect use.
