# YIMA: Period Tracking — Period Calendar

> Period Calendar (iPhone/iPad app by Haodong Ju.)

- Source: https://appshunter.io/ios/app/yima-period-tracking/id6761681327 (this page in markdown: same URL + `.md`)
- Developer: [Haodong Ju](https://appshunter.io/developer/1890849142)
- Category: Health & Fitness
- Price: Free
- Age rating: 4+
- Requires: iOS 18.0 · 37 MB
- Languages: English, Chinese
- Released: 2026-04-09
- Data updated: 2026-05-22
- User reviews in markdown: https://appshunter.io/ios/app/yima-period-tracking/id6761681327/reviews.md

## What is YIMA?

YIMA: Period Calendar is a beautifully designed, privacy-first menstrual cycle tracker built with love by the Novawerk open-source community.

YOUR PRIVACY MATTERS
All data is stored locally on your device. No accounts, no cloud sync, no tracking, no ads — ever. You own your data completely.

SMART PREDICTIONS
Record just 2-3 cycles and YIMA automatically predicts your upcoming periods, fertile windows, and cycle phases with increasing accuracy.

CYCLE AT A GLANCE
• Visual calendar with color-coded period days and predictions
• Real-time cycle phase indicator (Menstrual, Follicular, Ovulation, Luteal)
• Countdown to your next period with day-by-day tracking
• Bar chart showing cycle length trends with outlier detection

DAILY LOGGING
• Track flow intensity (Light, Medium, Heavy)
• Record your mood and symptoms
• Add personal notes for each day
• Backfill past periods anytime

DETAILED STATISTICS
• Average period and cycle length over last 6 cycles
• Visual cycle comparison chart
• Complete history with period and cycle data
• Easily spot irregularities

THOUGHTFUL DESIGN
• Material Design 3 with expressive shapes and animations
• Light and dark mode support
• Smooth page transitions and delightful interactions
• Available in English and Chinese (中文)

OPEN SOURCE
YIMA is built by Novawerk — open-source apps, made with care. View our code, contribute, or verify our privacy claims at github.com/Novawerk/yimalaile.

This app does not provide medical advice. It is for educational and planning purposes only.


## Version history (last 5 releases)

### 1.5.7 — 2026-05-18

Smoother onboarding: the "currently on period?" step now adapts to your situation — supports an active period without forcing an end date, and seeds an anchor cycle if you're unsure so predictions still work.

Tapping "Period started" in the calendar now defaults to the day you just tapped on (within the past week).

### 1.5.6 — 2026-05-12

- Refined home screen layout with better vertical balance and even spacing between sections.
- Internal cleanup for a leaner, cleaner build.

### 1.2.0 — 2026-04-14

1. added export feature, so we can share the reports

### 1.1 — 2026-04-12

1. fixed some performance issue

### 1.0 — 2026-04-09

No release notes.

## More apps by Haodong Ju

- [Berlin Chinese Food](https://appshunter.io/ios/app/berlin-chinese-food/id6766082989)

All apps by Haodong Ju: https://appshunter.io/developer/1890849142

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*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 2026-05-22.*