# Cycle Log - Calendar — Natural family planning method > Menstrual cycle calculator for identifying fertile and safe days. (iPhone/iPad app by Phan Nhat Đang.) - Source: https://appshunter.io/ios/app/cycle-log-calendar/id1621475818 (this page in markdown: same URL + `.md`) - Developer: [Phan Nhat Đang](https://appshunter.io/developer/1437390098) - Category: Utilities, Medical - Price: Free with in-app purchases - Rating: 4.92/5 from 13 App Store ratings · 3 written reviews indexed - Age rating: 12+ - Requires: iOS 15.0 · 2 MB - Languages: Czech, Danish, Dutch, English, Finnish, French, German, Indonesian, Italian, Japanese and 12 more - Released: 2022-05-21 - Data updated: 2026-06-10 - Monetization: freemium - User reviews in markdown: https://appshunter.io/ios/app/cycle-log-calendar/id1621475818/reviews.md ## What is Cycle Log? Use this app to monitor the phases of your menstrual cycle. To use this app effectively, you need to determine your cycle length. The cycle length is the number of days between periods, calculated from the first day of menstruation to the day before the next period begins. This is an intuitive, simple, and easy-to-use app. DISCLAIMER Important: The information and results provided in this app are for reference purposes only. This app is not a medical device and is not intended to diagnose, treat, monitor, or prevent any health condition, nor should it be used as a method of contraception, fertility assistance, or a substitute for professional medical advice. Menstrual cycles and ovulation timing may vary between individuals and from cycle to cycle, so results may not be accurate in all cases. Please consult a doctor or qualified healthcare professional regarding any reproductive health concerns. SUBSCRIPTION INFORMATION This subscription package offers users unlimited access to all app features throughout the subscription period. • Payment will be charged to iTunes Account at confirmation of purchase. • Subscription automatically renews unless auto-renew is turned off at least 24 hours before the end of the current period. • Account will be charged for renewal within 24 hours prior to the end of the current period, and identify the cost of the renewal. • Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user's Account Settings after purchase. • Any unused portion of a free trial period, if offered, will be forfeited when the user purchases a subscription to that publication, where applicable. Privacy Policy: https://13520178.github.io/CycleLog/policy.html Terms of Use: https://13520178.github.io/CycleLog/terms.html We are very happy to serve you. If you have any requests, don't hesitate to contact us. - phannhatd@gmail.com ## Key features - Menstrual cycle tracking - Fertile day identification - Safe day calculation - Intuitive interface - Cycle length input ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Annual Premium Package | $9.99 | per year | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Unlock all features | $2.99 | one-time | ## Recent user reviews (3 of 3) All indexed reviews: https://appshunter.io/ios/app/cycle-log-calendar/id1621475818/reviews.md ### 2/5 — Pay *2025-09-22* Not free. Cant even access a free version. Must pay as soon as you open the app ### 1/5 — No free trial or option *2024-09-04* Need to pay monthly ### 5/5 — Great app and Very Accurate! *2023-12-06* This is the most accurate tracking app I’ve used. It is really spot on for ovulation and safe days. I really like this app and hope it will soon offer a sharing option for your spouse. ## Frequently asked questions about Cycle Log ### How does Safe Days Calculator determine safe days? Safe Days Calculator determines safe days by analyzing your menstrual cycle length. You need to input your cycle length, which is the number of days from the first day of one period to the day before the next begins. The app then uses this information to calculate fertile and safe periods. ### What is the accuracy of Safe Days Calculator? The app states that the efficiency of the natural family planning method it uses is approximately 90%. It also includes a disclaimer advising users to seek a doctor's advice in addition to using the app and before making any medical decisions. ### Is Safe Days Calculator free to use? The app is free to download and use. It offers a subscription package for unlimited access to all features. A 7-day free trial is available for the Annual Premium Package. ### What are the subscription options for Safe Days Calculator? The app offers an Annual Premium Package for $9.99 per year, which includes unlimited access to all features. A 7-day free trial is provided with this subscription. ### Can I manage my subscription for Safe Days Calculator? Yes, subscriptions can be managed by the user. Auto-renewal can be turned off by going to your Account Settings after purchase. The subscription automatically renews unless turned off at least 24 hours before the end of the current period. ### What devices is Safe Days Calculator available on? Safe Days Calculator is available on iPhone, iPad, and iPod. It is designed for iOS devices. ### How often is Safe Days Calculator updated? The latest version of Safe Days Calculator is 2.0.0, and it was last updated on December 13, 2023. This indicates a relatively recent update frequency. ### What is the age rating for Safe Days Calculator? Safe Days Calculator has an age rating of 17+. This is likely due to the sensitive nature of the medical information it handles. ## Version history (last 4 releases) ### 2.3.0 — 2026-05-21 Bug fixes and performance improvements ### 2.0.0 — 2023-12-13 Bug fixes and performance improvements ### 1.1.0 — 2023-09-27 Bug fixes and performance improvements ### 1.0 — 2022-05-21 No release notes. ## More apps by Phan Nhat Đang - [Compound Interest Calc: Growth](https://appshunter.io/ios/app/compound-interest-calc-growth/id1437390099) - [Weight loss journal, diary](https://appshunter.io/ios/app/weight-loss-journal-diary/id1455057273) - [Basic grocery list + price](https://appshunter.io/ios/app/basic-grocery-list-plus-price/id1477000933) - [GFR Calculator - eGFR Calc](https://appshunter.io/ios/app/gfr-calculator-egfr-calc/id1485507590) - [Auto Loan Calculator - Car](https://appshunter.io/ios/app/auto-loan-calculator-car/id1487930075) - [Mortgage Calculator: Payment](https://appshunter.io/ios/app/mortgage-calculator-payment/id1489668528) All apps by Phan Nhat Đang: https://appshunter.io/developer/1437390098 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*