# Peak Flow Log vs Peak Flow Diary | Asthma

The clearest difference is ads: Peak Flow Log at none against Peak Flow Diary | Asthma's shown. Peak Flow Log also leads on review sentiment (100% vs 74%) and rating (5.0 vs 4.7). Peak Flow Diary | Asthma's advantage is ratings volume (36 vs 1) and iOS requirement (15.0 vs 26.2). On price, update cadence, in-app purchases and monetization model there is nothing between them.

Both are free to download. Peak Flow Log sells 1 one-off in-app purchase and Peak Flow Diary | Asthma sells 2 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

Peak Flow Log holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Peak Flow Diary | Asthma has 36 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Peak Flow Log's written reviews are positive against 74% of Peak Flow Diary | Asthma's.

Peak Flow Log ships an update every 2 weeks, Peak Flow Diary | Asthma every 3 weeks. The most recent releases landed on October 10, 2026 and October 27, 2026 respectively.

## The numbers

| Metric | Peak Flow Log | Peak Flow Diary | Asthma |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/peak-flow-log-asthma-diary/id867777007/reviews)** | [4.7 (36 ratings)](https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745/reviews) |
| Number of ratings | 1 | **36** |
| Positive reviews | **100.0% of reviews** | 74.2% of reviews |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 2 weeks** | Every 3 weeks |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 5 MB | 57 MB |
| Requires iOS | 26.2 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Friedrich Ewald](https://appshunter.io/developer/867777010) | [Keyber Inc.](https://appshunter.io/developer/1571255559) |

## What reviewers say

### Peak Flow Log

[App page](https://appshunter.io/ios/app/peak-flow-log-asthma-diary/id867777007)

This app helps you monitor your asthma and peak flow readings. It uses a color-coded system to indicate the quality of your measurements. Additional features are available through a premium version.

**Highlights:** Track asthma and peak flow, Color-coded value indicators, Premium features available, Feature requests welcome

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Peak Flow Log Plus | $0.99 | one-time |


### Peak Flow Diary | Asthma

[App page](https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745)

Easily record daily peak flow values and visualize breathing changes with clear graphs. Understand your asthma trends, identify early warning signs, and support your health management. Useful for medical visits and daily care.

**Highlights:** 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

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Plan | $3.99 | per month |
| Annual Plan | $24.99 | per year |


## Frequently asked questions

### Is Peak Flow Log free?

Peak Flow Log is free to download, with in-app purchases available.

### Is Peak Flow Diary | Asthma free?

Peak Flow Diary | Asthma is free to download, with in-app purchases available.

### Which has better reviews, Peak Flow Log or Peak Flow Diary | Asthma?

Peak Flow Log is rated higher. Peak Flow Log averages 5.0 out of 5 from 1 ratings, while Peak Flow Diary | Asthma averages 4.7 from 36 ratings.

### Do Peak Flow Log or Peak Flow Diary | Asthma have ads?

Peak Flow Diary | Asthma shows ads; Peak Flow Log does not.

### Which is updated more often, Peak Flow Log or Peak Flow Diary | Asthma?

Peak Flow Log ships an update every 2 weeks, and Peak Flow Diary | Asthma every 3 weeks. Most recently, Peak Flow Log was updated on October 10, 2026 and Peak Flow Diary | Asthma on October 27, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*