# Peak Flow Diary \| Asthma — Understand Your Breathing

> Asthma peak flow tracker with graphs and cloud storage. (iPhone/iPad app by Keyber Inc..)

- Source: https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745 (this page in markdown: same URL + `.md`)
- Developer: [Keyber Inc.](https://appshunter.io/developer/1571255559)
- Category: Medical, Health & Fitness
- Price: Free with in-app purchases
- Rating: 4.70/5 from 35 App Store ratings · 29 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.0 · 57 MB
- Languages: American English, Japanese
- Released: 2023-09-18
- Data updated: 2026-09-10
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745/reviews.md

## What is Peak Flow Diary | Asthma?

Understand Your Breathing, Every Day.

Peak Flow Diary is an easy-to-use app that helps you record your daily peak flow readings and track changes in your breathing over time.

With just a few seconds of recording each day, you can better understand:

• Your usual breathing condition
• Changes and trends in your breathing
• When your condition starts to worsen

Color-coded zones make it easy to see your current breathing status at a glance, helping you manage your respiratory health every day.

【Key Features】

■ Quick and easy daily recording
Record your peak flow in seconds using either the slider or keyboard input.
Choose the method that works best for you.

■ Color-coded graphs
View your peak flow readings in easy-to-read graphs.
Color-coded zones help you quickly understand your current condition and identify trends over time.

■ History and notes
Review all your previous records in one place.
You can also save notes about your symptoms, activities, or daily events.

■ Medical Report (PDF)
Automatically generate a PDF medical report from your recorded data.
Print it or show it on your smartphone to help explain your condition during medical appointments.

■ Reminder notifications
Set reminders so you never forget to record your peak flow.

■ Secure cloud backup
Your records are safely stored in the cloud, making it easy to restore your data when changing devices.

■ Simple and intuitive design
Designed to be easy to use every day, so you can build a lasting habit.

【Premium】

Unlock additional features to gain deeper insights into your breathing.

■ Breathing Monitor
Analyzes your daily peak flow readings and sends push notifications when sudden drops or declining trends are detected.

■ Long-term analysis
View your peak flow data over an entire year to identify long-term trends that may not be visible within just 28 days.

■ Comparison graphs
Compare your current data with the previous year to better understand seasonal changes and long-term patterns.

■ Extended Medical Reports
Generate PDF medical reports covering up to one year of recorded data.

■ Ad-free experience
Enjoy the app without advertisements.

Keeping a daily record is the first step toward better understanding your breathing.

Start tracking your breathing today with Peak Flow Diary.

Peak Flow Diary Terms of Service
https://susatthi-asthma-diary-prod.web.app/terms-of-service.html?lang=en

Peak Flow Diary Premium Terms of Service
https://susatthi-asthma-diary-prod.web.app/terms-of-service-premium.html?lang=en

## Key features

- Daily peak flow recording
- Easy input methods (slider/keyboard)
- Zone-based graph display
- Record list with memo management
- Cloud storage and account support
- Intuitive and simple operation

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Annual Plan | $24.99 | per year |
| Monthly Plan | $3.99 | per month |


## Recent user reviews (10 of 29)

All indexed reviews: https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745/reviews.md

### 4/5 — 使いやすい

*2026-08-06*

難しい操作がなく使いやすい。
ひとつだけ不便なことは日付ではなく曜日表示なのでピークフローが下がっている日をわざわざ曜日と手持ちのカレンダーを照らし合わせないといけない事ですかね

### 5/5 — スマホで安心がたまる🩷

*2026-05-20*

スマホは中毒のように朝起きた時から夜寝る時までさわる。起きた時と寝る前にピークフローメーターを3回、その場のスマホいじりの延長で安心が勝手にたまって行く。これはポイントが貯まる感覚で続けられる！まさか自分の喘息（呼吸苦）をこんなに可視化できると思わなかった！
良い時代になりました！
アプリ開発者様、ありがとうございます！！！

**Developer response:** コメントありがとうございます！開発の励みになります！

### 5/5 — 素晴らしい

*2026-05-16*

今まで手書きしてました。
ありがとございました。

**Developer response:** コメントありがとうございます！開発の励みになります！

### 4/5 — Good to great

*2026-04-18*

What would make this app better is to be able to edit the areas of what’s good and what’s are of concern to our own asthma plan

**Developer response:** We appreciate your suggestion regarding the customization of the asthma plan areas. We understand how important it is to align the app with your personal medical plan and will look into this feature.

### 3/5 — Cannot adjust the traffic light system

*2026-04-16*

Following being poorly and having peak flow done, I was told that if my peak flow is at 200 as this is below 50% of my normal peak flow - however the app states 100 is the action required - would be helpful if people could adjust the warning states based on the recommendation from their healthcare professional advice. Sadly based on this I have deleted the app as it is not useful for me.

**Developer response:** You can manually adjust your personal best peak flow value in the settings. We would love for you to give it another try!

### 4/5 — 概ね満足していますが

*2026-04-05*

いつのまにか折れ線グラフが点だけになり線で繋がらなくなってしまった。改善方が分かると嬉しい。

**Developer response:** 期間「月」を選択したときに線が表示されない問題を修正しました！今後ともご利用お願い致します！

### 4/5 — 使いやすいです！

*2026-03-04*

ピークフローで喘息を管理しているので、毎日使わせていただいています。操作性もよく、とても使いやすいです。
一つ、お願いがあります。
ピークフローの数値は入れなくてもメモだけで残せるようになるとありがたいです！出先などで、体調だけを記録に残したいことがあるので…
今後も使わせていただきますので、よろしくお願いいたします！

追記:有料でも構いませんので、完全に広告が消せると嬉しいです。

**Developer response:** ありがとうございます！検討致します！

### 5/5 — 最高のアプリです！

*2026-02-17*

喘息患者です、とても使いやすくて助かりました！
毎日使うものなので、直感的に操作方法がわかってありがたいです。
立ち上がる度に記録がサクッとつけられてストレス無しです。
クラウドで記録も保存できますし、痒いところまで行き届いて安心です。
とても良いアプリを制作いただきありがとうございます。

**Developer response:** フィードバックありがとうございます！開発の励みになります！

### 4/5 — Print

*2026-01-26*

I live the app but there should be a way to print out all your data thanks

**Developer response:** Thank you for your feedback! We will certainly consider adding a print feature in a future update.

### 5/5 — Easy to use and useful

*2025-12-10*

Very easy to use and keep track of your asthma.

**Developer response:** Thanks for using it!

## Frequently asked questions about Peak Flow Diary | Asthma

### How does Peak Flow Diary help manage asthma?

Peak Flow Diary allows you to record daily peak flow values and visualize trends through easy-to-read graphs. This helps you understand your condition, identify early signs of worsening symptoms, and have better data to discuss with your doctor.

### What are the input methods for peak flow in Peak Flow Diary?

Peak Flow Diary offers two convenient input methods for recording your peak flow values: a slider for quick adjustments or a keyboard for precise entry.

### Can I see my past peak flow data in Peak Flow Diary?

Yes, Peak Flow Diary provides a record list where you can review all your past peak flow entries. You can also add notes to each record for better reflection and context.

### Is my data safe with Peak Flow Diary?

Peak Flow Diary utilizes cloud storage and account support to securely store your data. This ensures your information is safe and can be restored if you change devices or lose your current one.

### What devices does Peak Flow Diary support?

Peak Flow Diary is available for iPhone, iPad, and iPod devices, allowing for consistent tracking across your Apple ecosystem.

### How often is Peak Flow Diary updated?

The app was last updated on March 20, 2026, indicating ongoing development and support for the application. The latest version is 4.14.0.

### What is the age rating for Peak Flow Diary?

Peak Flow Diary has an age rating of 4+, making it suitable for a wide range of users who need to track their asthma.

### Is Peak Flow Diary free to use?

Yes, Peak Flow Diary is free to download and use. It also includes ads to support its continued development.

## Version history (last 5 releases)

### 6.1.0 — 2026-09-08

- Updated the libraries used by the app
- Fixed minor bugs

### 6.0.2 — 2026-08-06

Introducing Premium!

[New]
- Added Premium
- Added Breathing Monitor (Premium only)
- Added Graph Comparison (Premium only)

[Improvements]
- Improved the Medical Report design
- Changed graphs to display the most recent dates instead of - Monday-based weeks
- Improved the UI/UX for a better experience
- Adjusted ads in the free version
- Updated the libraries used by the app
- Fixed minor bugs

### 5.5.1 — 2026-06-15

- Fixed an issue where an error was displayed after recording peak flow values.

### 5.5.0 — 2026-06-12

- Fixed an issue where reminders may not be cleared
- Improved the initial setup to allow registering multiple reminders
- Enabled reminder notification sounds
- Updated internal libraries used in the app
- Minor design improvements
- Minor bug fixes

### 5.4.0 — 2026-06-06

- Implemented reminder functionality
- Added initial setup flow
- Updated libraries used in the app
- Minor bug fixes

## Apps similar to Peak Flow Diary | Asthma

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Airyn, the asthma app](https://appshunter.io/ios/app/airyn-the-asthma-app/id1641811087) | — | Free | Medical |
| [Peak Flow Log - Asthma diary](https://appshunter.io/ios/app/peak-flow-log-asthma-diary/id867777007) | 5.0 (1) | Free | Medical |
| [Daily Breathe: Asthma Tracker](https://appshunter.io/ios/app/daily-breathe-asthma-tracker/id6477149460) | 4.9 (28) | Free | Medical |
| [Asthma: Tracker & Reminders](https://appshunter.io/ios/app/asthma-tracker-and-reminders/id6744072783) | 5.0 (4) | Free | Medical |
| [Asthma Manager](https://appshunter.io/ios/app/asthma-manager/id930678066) | 3.3 (4) | Free | Medical |
| [Peflog - asthma tracker](https://appshunter.io/ios/app/peflog-asthma-tracker/id1212024484) | 2.0 (3) | $1.99 | Medical |

## More apps by Keyber Inc.

- [確定申告がラクになる医療費管理](https://appshunter.io/ios/app/id1571255557)

All apps by Keyber Inc.: https://appshunter.io/developer/1571255559

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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 2026-09-10.*