iPhone Screenshots


To all the women who need a calendar to write down upcoming period
To all the women who need a journal to manage irregular period cycle and cramp
To all the women who want to know ovulation, fertile, birth control, and possibility of pregnancy all in one calendar
To all the women who were bothered to mark their period on the calendar
To all the women who secretly recorded symptoms on their planner
Must-have! Period tracker, Once!
[Kept both simplicity and functionality of period tracker!]

** Estimated period calendar which gets more accurate as you use it!
Once automatically calculates your irregular period cycle and cramp smartly!
In the period calendar, you can view your estimated period, fertile which has high percentage of pregnancy, and ovulation, all in one-step! In the calendar history list, you can view all your past period cycle in one-step.

** Take care of your fertile and ovulation meticulously!
You can take care of yourself even better with the calendar which shows fertile, ovulation, and estimated period in a glimpse of eye!

** A widget which allows you to check precious data quickly!
The first period calendar ever! Check the important info (estimated period, ovulation, and percentage of pregnancy) more quickly and easily with our widget.

** Percentage of pregnancy calculated scientifically!
Based on egg’s duration of life, 24hrs, and sperms’ duration of life, 3~5 days, we indicate percentage of pregnancy “high” for one day before and after the ovulation, and “moderate” for fertile.

** The day you must be prepared! Prepare it in advance!
To make you not embarrassed on the day! We notify the important dates (estimated period, ovulation/fertile and whenever you want) you in advance with witty message and alarm. We provide the alarm function of contraception pills.

** Keep your precious daily data conveniently!
Keep your data easier than a journal. All your recorded period, intimate days, memo, and automatically calculated ovulation and fertile… and all other data… You only need to sign-up to keep them all!

** Not just your period, but your secret intimate days!
You can record your status and symptoms such as the first day of period and period cramps, whenever you want.
Once, which you can record all your secrets such as intimate days! Don’t worry about others having a look at your diary, with our lock function.

** Simple and stylish design capturing women’s mind!
“The better it looks, the more convenient to use.” We have enhanced usability of calendar, by simple and stylish design. In the period calendar, you can view your estimated period, and ovulation, all in one-step. Just like a pretty planner you want to show off, the calendar design won’t be embarrass you even when you install it!

[We have added special features only available in Once!]

** Charming and interesting “Today’s Tip”, which changes depending on your cycle!
Beauty tips which makes you attractive and charming depending on period cycle, ovulation, and fertile. Useful real-life know-hows, useful diet tips, tips to prevent pregnancy, tips for healthy relationships… we enhance your charm by providing various tips!

** Once events made exclusively for women!
Staring from Once beauty pouch fully packed with sense, and Once doctor which provides exact information on diet and health… We hold various events on beauty, diet, and health, which suits women’s appetite!


Please be with Once, we are doing our best to bring you the best service :D
Developer: Malang Studio (http://malangstudio.com/)

* You can get faster response for questions regarding Once if you write to once@malang.kr!

What's New

Version 1.3.17

Fixed bugs.

Ratings and Reviews

4.2 out of 5

10 Ratings

10 Ratings

Cute app


Good tracker that’s flexible to use and allows you to input important details. Love the slideshows that change daily with tips coinciding to where you are with your period. Been using this one for a few years now. Super cute.



Been using this app for about a year . I love it, and it's very accurate. Definitely recommend!

No Ad Free Options


Can’t make a one time purchase to get rid of ads, you have to pay monthly instead.


Malang Studio Co. Ltd,
50.8 MB
Health & Fitness
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, Japanese, Korean, Simplified Chinese, Thai, Traditional Chinese
Age Rating
Rated 12+ for the following:
Infrequent/Mild Medical/Treatment Information
Infrequent/Mild Sexual Content and Nudity
Infrequent/Mild Mature/Suggestive Themes
© Malang Studio Co. Ltd,
In-App Purchases
  1. Ad-Free Ticket (30days) $0.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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