Original photo by Claudio Alvarado Solari

Five things to think about when designing a period tracking app

This is a three part series on period tracking, co-authored with Daniel Epstein, based on a study we completed at the University of Washington. Part 1 explains our research and discusses why and how people track their periods. Part 2 is a discussion about how we can use this information to design better period tracking tools. Part 3 is an exploration of what it’s like to study women’s health as a male researcher.

In our last post, we talked about what we learned about how and why people track their period. In this post we’re going to discuss how people feel about the period tracking apps that they’ve used. We’re also going to outline simple things that app builders can do to make people happier.

All of these recommendations are based on cold, hard research — the things we learned from reading 2000 app reviews of period tracking apps, surveying almost 700 people on how they track their periods, and performing in-depth interviews with 12 people. We’re making this information publicly available because we believe that this an important health topic, and we want to help app builders create better tools for everyone.

Accuracy is table stakes

Unsurprisingly, the most important thing that a period tracking app does is tell someone when they are going to have their period (and for many people, when they are ovulating). We read 367 app reviews (out of 2000) that talked about accuracy, either praising their app’s ability to learn their cycle or complaining about its limitations. People rely on these predictions in order to be prepared for their period. They need their app to be accurate.

Predictions are generally pretty good for someone with a regular cycle who diligently records in the app whenever their period begins and ends. But for people with more irregular periods, accuracy can be so bad that an app’s predictions are meaningless. Apps rarely give users a way to track common things that impact period cycles, like stress and extreme physical activity. Some apps don’t even have a pregnancy mode — one user’s app review said that her app thought she had a 700-day cycle!

Apps also assume that users will be consistent about logging when the start and end of their period. Plenty of people simply forget to log this data. And because apps use past data to predict future periods, forgetting can mess up predictions for months.

The whole reason I need a period app is due to my extremely irregular periods… For someone whose days vary it’s hard to use. Sometimes my periods are longer than normal and the app assumes I must have forgotten to hit the ‘period end’ button and does it for me.
“If something out of the ordinary happens (Plan B, particularly stressful month), it doesn’t take that into account when predicting your next period.”
I sometimes forget to enter my data one month, which skews the data for the next month.

Our recommendation

Because predictions are so important, app designers should explore more ways to model and communicate predictions about the user’s cycle. No app is going to perfectly predict every person’s cycle, and users need to be able to understand and compensate for flaws in the prediction algorithm. Furthermore, people use prediction information in multiple ways. Needing a heads up that your period is coming tomorrow is a totally different scenario than figuring out what you need to pack for your 2 week vacation. Apps should help users handle both situations.

On top of that, apps need to acknowledge that everyone has their own reasons for tracking. Someone who is trying to avoid becoming pregnant would probably prefer that their app overestimate their ovulation window. On the other hand, someone who is trying to become pregnant probably wants a more conservative estimate of their ovulation window so that they can time conception accurately. In both cases, a binary prediction of whether or not ovulation is happening is misleading. Designers should find better ways to show the uncertainty and error margins of the prediction algorithm their app uses.

App predictions ignore relatively common things that can impact someone’s menstrual cycle, like high stress or disruptive diet changes, and don’t give users a way to correct the app or mark why their cycle was irregular. Apps should give people a way to record when the app’s prediction falls out of line with when their period actually occurs, and the app should use this information to improve prediction accuracy. We should always be looking for more ways to account for natural variation in people’s cycles so that tracking accuracy gets better for everyone.

People don’t want to flaunt their period

Most people want to keep their menstrual cycles to themselves. We heard from multiple participants who worried about accidentally disclosing where they are in their cycle when sharing their calendars or phones with friends and coworkers. Others were worried that people around them might notice an obvious period app up on their phone screens.

Some people are so concerned with privacy that they “encode” events in their calendar with symbols or code words. Some even refuse to use a calendar or app because they are worried that others will see their data. The way that most period tracking apps are designed only amplified this problem. Period tracking apps tend to be fairly pink, which can draw immediate attention from others. They often include “period” in the name of the app. And some apps send loud notifications right before a period is expected to arrive.

It’s weird having it on my calendar so publicly, I wish it was there but somehow more secretly
I used to be embarrassed when other people looked at my phone and saw a bright pink tracking app
I renamed the app ‘tracker’ on my phone instead of ‘period tracker

Our recommendation

Period tracking apps should give people a way to customize their experience and make their app stand out less. Every app should have a discreet, neutral skin, either as the default or as a custom option. Many of the people we studied want app color schemes, icons, names, and notifications that do not shout “I’m tracking my period now!” to whoever happens to glance at their phone.

Along these lines, designs should give users a way to disable and customize the notifications. Apps shouldn’t show personal tracking data to strangers, including shoulder surfers, unless the user specifically wants that.

Pink is a turnoff (and other ways that apps are too heteronormative)

Most of the apps we saw used pink, flowery, stereotypically feminine designs. People told us that these designs made tracking less serious or important than they wished. Some apps also prominently feature sex and ovulation alongside period tracking. While tracking ovulation is an important feature for some people, others wish it was de-emphasized or that they could hide that functionality.

The app P. Tracker Lite uses prominent, eye-catching imagery of flowers and butterflies and has a large, pink button to mark the start of a period.
The app Life uses large imagery of pink flowers and displays both period and ovulation information prominently.

Apps also generally assume that the person tracking is both straight and identifies as female. The app Clue uses icons that suggest a male partner, accidentally implying that users only need and want to track sex with male partners. The educational information about sex in Clue focuses almost entirely on fertility, ignoring other reasons why someone might want to track their sexual activity (for example, many participants logged sexual activity to keep a pulse on their relationship with their partners). The app Glow sends anyone who identifies as “male” to an alternate view of the app that doesn’t let them track menstrual cycles.

The app Glow assumes a female user and offers three different goals: avoiding pregnancy, trying to conceive, and fertility treatments. It has a smaller, fourth option for male users.
The app Clue allows users to log unprotected or protected sex, and uses a figure with a tie (coded male) to signify protected sex.
they have tried to make it ‘feminine’ by adding flowers… It makes me feel like you are trying to ‘dumb it down’ for me. Why can’t keeping track of my menstruation be a professional and organized task?
as someone in a same sex relationship protection isn’t really a concern, but I would like to keep track of my ‘activity’ levels.
it’s an amazing app, but it’s meant for straight couples.

Our recommendation

As we discussed in the previous section, a lot of people don’t want their period tracking app to be flashy, attention grabbing, or obviously about periods. Tools shouldn’t assume that a user is super feminine, and they also shouldn’t push gender in their labels, iconography, and functionality. It’s very little work for app builders to stay gender-neutral (design like every other app!), and it means the world to quite a few users.

Similarly, apps that support logging sexual activity should be careful not to assume the sexual orientation or gender of either the person logging or their partner(s). Logging sex and reporting fertility is very desirable for some women — and downright uncomfortable for others. It’s great to design in features to support tracking sex and fertility, but it should also be easy for users to turn those features off.

Data is for using

There are lots of ways people wanted to use and understand the data from their period tracking apps. Some apps support journaling mood, headaches, insomnia, and sexual activity, which people used to find patterns in their overall health. Others used other apps and devices to track their fitness, noticing interesting correlations between their cycle and their physical activity. Comparing data and making these connections can be difficult, because many period tracking apps do not give users a way to import or export data.

Tracked period data can also inform conversations with doctors. These conversations tended to go best when a user had a specific health concern related to the data, like trouble getting pregnant or an irregular or painful cycle. Participants told us that they felt like their doctors didn’t have much time to engage with the data. Many prepared their own summaries and charts to make the conversation easier.

I was consistently being depressed right before it happened. I would be really unhappy and grumpy, and then I’d get my period.”
I have noticed a connection between my resting heart rate and my menstrual cycle… [but] neither my menstrual cycle app nor the Fitbit allow me to export the data, so I have to manually type the data into a spreadsheet to see the trend. I’d love it if I could export the data, or if I could track both via one app.
[the doctors] don’t have much time, I felt like if I had just printed off the massive spreadsheet and handed it to them, there’s pretty much zero chance they would have looked at it… I really tried to just summarize it, and give them a 1 or 2-page sheet… they loved that… otherwise they have to go through my record, which is a massive packet of stuff.”

Our recommendation

Menstrual cycles are an important part of people’s health. They affect, and are affected by, many aspects of life and can be an important early sign of health changes. Period tracking apps should help users make connections and spot problems early.

Journaling alongside period tracking is a powerful way for users to make connections between their menstrual cycle overall wellbeing. Tracking factors like mood and stress, as well as creating a way to track open-ended things, will help users better understand their bodies. All apps should also give users a way to export their tracked data, ideally in a format that is compatible with other popular platforms for tracking health data (like Fitbit, Apple Health, or MyFitnessPal). It should also be easy to summarize and export this data for healthcare providers, to support a more holistic view of a patient’s health.

Tracking goals change over time

As we mentioned in our previous post, there are a lot of different reasons why people track their periods. These reasons can and often do change over time. Some people started tracking to be prepared for their period, and now track to avoid becoming pregnant. Some started tracking to become pregnant, and now track as a general health check. Others have had ups and downs with fertility, but still find value in tracking their cycle.

Apps aren’t terribly successful at helping people migrate between these goals. Some apps are better for providing information about fertility or post-partum health issues. Others are better at educating people who are just starting to get their period. This type of specialization is common in the world of app design. The problem is that what users value above all else is accuracy. Because period tracking apps learn people’s cycles over time, people will often stick with an app which doesn’t support their current goals so that they don’t have to start tracking all over again. Other people juggle two apps at once, tracking their periods in both places (which is twice as much work).

I initially started because I was fairly irregular and wanted to find any trend I could. Now I track to make sure I’m not missing my period — a pregnancy check, basically.
Some [apps] have features for health and some have features for fertility planning… to make the most, I have used various apps at the same time and entered data into them twice.
my app shows predicted ovulation. I wish it didn’t. We dealt with infertility and extensive treatments for 6 years. I am no longer trying to get pregnant and I don’t like the reminder of TTC [trying to conceive] or the tiny glimmer of hope that maybe by magic this will be the month when a miracle happens.
I would like it if they made a kid’s version because idc [I don’t care] about fertile!! I’m too young!!

Our Recommendation

People’s goals and motivations change over time, and period tracking apps should change along with them. For example, apps can provide a special view when someone begins trying to conceive, using their menstrual cycle history to accurately predict when they will ovulate. This goes hand in hand with acknowledging that not everyone needs the same thing from their period tracking app. A 12-year-old experiencing their first period is just starting to learn about their body. A 22-year-old with endometriosis wants to manage their symptoms. A 45-year-old who has stopped trying to conceive after a string of miscarriages doesn’t want to be reminded of their ovulation cycle.

Apps that don’t support changing goals over time should make it easy for users to export their menstrual cycle history, or share data among a collection of apps, so people can move their data to an app tailored to their new goal. Even without a specific goal change in mind, users benefit from being able to get their tracked data outside the app — whether they are trying to share their information with a healthcare provider or just moving to a new phone.


It would be irresponsible of us not to mention that there are apps which succeed at some, or even many, of the points we discuss here. But we have yet to find an app that succeeds at all of them. Most of the people who we surveyed and interviewed were generally unhappy with the landscape of period tracking apps available to them. We found a common pattern: people try multiple apps, and then settle for whichever one has the fewest problems for their current situation (nevermind what they might want from an app in the future).

I’ve tried 4 apps. They all suck… I would think a creative woman would’ve created something better by now…

Designers, engineers, and researchers can and should do better. These apps are used by large portions of the population on a monthly or even daily basis. People clearly desire better options. It’s up to us to create those better options.

Stay tuned for part 3 of this series, where Daniel reflects on what it’s like to be a male researcher studying a women’s health topic.


The research summarized here was completed at the University of Washington by Daniel Epstein, Nikki Lee, Jennifer Kang, Elena Agapie, Jessica Schroeder, and Laura Pina with feedback, mentorship, and advice from James Fogarty, Julie Kientz, and Sean Munson. This work has been conditionally accepted for publication at CHI 2017, a leading conference on human-computer interaction.

The original research publication, which includes additional content and references to many more relevant academic studies, can be read in its full form on Daniel Epstein’s website.