# iSpirometry vs Peak Flow Diary | Asthma

The clearest difference is review sentiment: Peak Flow Diary | Asthma at 74% against iSpirometry's 0%. Peak Flow Diary | Asthma also leads on rating (4.7 vs 3.4) and update cadence (every 3 weeks vs every 2 months). iSpirometry's advantage is in-app purchases (none vs 2) and ads (none vs shown). On price and device support there is nothing between them.

Both are free to download. Peak Flow Diary | Asthma sells 2 in-app purchases, starting at $3.99 per month. iSpirometry asks for nothing beyond the download.

Peak Flow Diary | Asthma holds the better App Store score, 4.7 against 3.4. That said, the two scores are not equally well evidenced: Peak Flow Diary | Asthma has 36 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 0% of iSpirometry's written reviews are positive against 74% of Peak Flow Diary | Asthma's.

iSpirometry ships an update every 2 months, Peak Flow Diary | Asthma every 3 weeks. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.

## The numbers

| Metric | iSpirometry | Peak Flow Diary | Asthma |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.4 (5 ratings)](https://appshunter.io/ios/app/ispirometry/id1367895022/reviews) | **[4.7 (36 ratings)](https://appshunter.io/ios/app/peak-flow-diary-asthma/id6463603745/reviews)** |
| Number of ratings | 5 | **36** |
| Positive reviews | 0.0% of reviews | **74.2% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 6 MB | 57 MB |
| Requires iOS | **8.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [MIR Medical International Research](https://appshunter.io/developer/1010662698) | [Keyber Inc.](https://appshunter.io/developer/1571255559) |

## What reviewers say

### iSpirometry

[App page](https://appshunter.io/ios/app/ispirometry/id1367895022)

This app works with a specific spirometer device to measure key respiratory health metrics. It provides real-time data, intuitive guidance for performing tests, and stores results with additional notes for easy interpretation and sharing.

**Highlights:** Bluetooth spirometer connectivity, Real-time respiratory measurements, Intuitive test performance animation, Comparison to target values, Quality control grading, Test result storage and notes, PDF report generation

**Features:** macOS Compatibility

**In-app purchases:** none


### 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 iSpirometry free?

iSpirometry is free to download, with no in-app purchases.

### Is Peak Flow Diary | Asthma free?

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

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

Peak Flow Diary | Asthma is rated higher. iSpirometry averages 3.4 out of 5 from 5 ratings, while Peak Flow Diary | Asthma averages 4.7 from 36 ratings.

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

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

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

iSpirometry ships an update every 2 months, and Peak Flow Diary | Asthma every 3 weeks. Most recently, iSpirometry was updated on October 24, 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.*