Lily - Fertility Calculator 9+

Reliable and natural

Whimsical Inc.

    • 4.7 • 142 Ratings
    • Free
    • Offers In-App Purchases

iPhone Screenshots


Lily is a remarkably powerful, yet beautiful and easy way to determine the fertile and infertile phases of your cycle. It is the perfect tool for you to learn more about your body, while being discreet, reliable, and absolutely private!

You want to learn more about Lily and how it works? Head over to for more detailed information!
Once there, make sure to take a quick look at our privacy policy as well. We are absolutely sure that you will love what you can read there!

Lily lets you evaluate your cycles either based on averages (comparable to the calendar method,) or based on your body's own symptoms using either FAM/NFP (Fertility Awareness Method/Natural Family Planning) from the US, or NFP (AG NFP) developed by workgroup NFP from Germany. Your choice!

Lily can be a great little helper for you to achieve your family planning goals, and it works incredibly well for both: women who are trying to conceive, as well as women who are trying to avoid a pregnancy. Lily is also used by many women who simply want to learn more about their own body!

Evaluating your cycles based on averages is easy as pie, but a little less accurate. And even though the evaluation of your cycles based on your body's own symptoms requires a little more effort, Lily will be able to evaluate your fertility much more accurately – which is especially important if you want to use Lily to help you avoid a pregnancy.

If you want to use Lily's averages-based evaluation method, you can start right out of the box. All you need is the starting day of your past period, or two.

To successfully evaluate your cycles using one of Lily's symptoms-based evaluation methods, all you need is a thermometer labeled for taking your basal body temperature with two decimals behind the dot for °C, or with one decimal for °F – and that's it! You don't need to know or learn any complicated rules, Lily will do the work for you!

Lily also includes these features:
• see the time you are most fertile during your cycle and an estimated for the begin of your next period
• predict your 12 upcoming cycles
• charting of your temperature (Fahrenheit or Celsius)
• charting of your cervical fluid and its changes throughout the cycle
• view your data in the graph and calendar and get detailed information for every day by the touch of a finger
• add details on your love life (with or without protection)
• record interferences that may have lead to higher temperatures
• record period flow and associated symptoms
• record your mood
• password-protect your data
• an extensive in-app help
• discreet name and icon to avoid awkward moments

You can unlock even more features with an in-app purchase (We do have to pay our bills somehow!):
• more tracking menus: Cervical Position, Secondary Symptoms, Custom Notes, Medication, Diary, LH/OPK Test Results, and Menopause Symptoms
• rearrange the 'Your Data' menu, as well as the ability to hide tracking menus you don't need
• a dark theme, including the ability to let Lily switch between the dark and the light theme automatically depending on the time of day or your display brightness
• print your charts and data via AirPrint, or export and send them as PDF documents via email to your physician or anyone else you like
• smart reminders that tell you whenever Lily still waits for important data
• custom reminders for anything you want
• change Lily's pink to any hue you like

Lily was not developed to diagnose, treat, prevent or cure any medical conditions. For any medical related questions, please see your physician.

By using Lily you agree that Whimsical Inc. does not guarantee the method of birth control or pregnancy achievement and is not to be hold liable for an unwanted pregnancy or the unsuccessful attempt to conceive.

What’s New

Version 3.7

We have updated a few things under the hood and fixed a number of usability issues and minor bugs.

Ratings and Reviews

4.7 out of 5
142 Ratings

142 Ratings

adamellite ,

Great app for tracking

Having tried a couple other apps, Lily is my favorite. It does exactly what I need it to do. Other apps ask for temperature, cervical fluid quality, etc, but don’t always use it in estimating ovulation. Lily is very clear and user friendly. The documentation is very understandable. I thought I fully understood my cycles prior to using Lily, but I realized I was wrong about a few things. I do understand my body a lot better now, and I highly suggest this app. I am a scientist by training, and I love data. Lily is fun to use, and the charting makes it easy to visualize.

Another important feature is that Lily data is completely stored on your phone so you are the only one with access to the data (or anyone you share it with).

Although I didn’t need to purchase anything to get all data from Lily I did anyway to support the company. It’s relatively inexpensive and a one time fee. If you have a couple extra bucks I recommend paying it just to support the app creator and keep this app available!

Broke Driver ,

The Best

Excellent app. I’ve tried Kindara, FEMM, Ovy, Glow, you name it, and Lily beats them all. Other apps have childish, clunky interfaces, or they spam you with nutrition/horoscopes/life advice. I love that Lily does! Lily lets you customize the way the app looks, switch between viewing your temp chart at vertical or horizontal with 2 clicks, and has been the most accurate app for me in terms of period charting. It gives you averages, a cover line, and counts the days automatically so you don’t have to think about it, and gives you lots of options for what you do/don’t want to track. The only things I dislike are minor (I wish I could customize the cervical fluid/period colors as well, or that they automatically adjusted with any new color scheme to be a little less jarring). I also wish the cervix position icon were slightly larger, or maybe had thinner lines as it’s a little hard to see. But, I love that the Lily app doesn’t force Bluetooth on me. 5 Stars!

delicious natalicious ,

Comprehensive, clean interface

Well worth paying for premium features, IMO. Many fertility trackers are primarily geared towards women trying to conceive. Period trackers can be more neutral, but they tend to be very limited in their scope. Lily supports all women’s reproductive goals, whether it’s trying to conceive, trying to avoid, or simply getting a feel of your cycles.

I’m in the “preconception” phase, in which I’m closer, my IUD is out, I’m taking my prenatals, I’m temping using a TempDrop or oral BBT thermometer, but I’m not actively trying. This has been a great way to monitor myself.

I’m tracking my temperature, thermometer used (a feature I can only use with the paid custom tracking option), times having sex and any applicable birth control method (Lily lists so many, from barriers, hormonal, and pull-out), and period. Lily has both a beautiful graph and a calendar marking my expected period dates.

App Privacy

The developer, Whimsical Inc., has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.

You Might Also Like

Health & Fitness
Health & Fitness
Health & Fitness
Health & Fitness