# KetoAir vs MetFix

The clearest difference is in-app purchases: KetoAir at none against MetFix's 4. MetFix's advantage is update cadence (every 4 days vs every 2 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. MetFix sells 4 one-off in-app purchases. KetoAir asks for nothing beyond the download.

KetoAir ships an update every 2 months, MetFix every 4 days. The most recent releases landed on October 6, 2026 and October 22, 2026 respectively.

## The numbers

| Metric | KetoAir | MetFix |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.5 (2 ratings)](https://appshunter.io/ios/app/ketoair/id1671355214/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 days** |
| Monetization | Free | — |
| Size | 60 MB | 84 MB |
| Requires iOS | 16.4 | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [Qi Diagnostics Limited](https://appshunter.io/developer/1636454031) | [Break Even Productions](https://appshunter.io/developer/6822868144) |

## What reviewers say

### KetoAir

[App page](https://appshunter.io/ios/app/ketoair/id1671355214)

This device and companion app help you monitor your body's fat-burning status by measuring acetone levels in your breath. Get instant, accurate results to understand how your diet and exercise affect your ketosis.

**Highlights:** Instant breath acetone measurement, Accurate real acetone sensor, Bluetooth device connectivity, Log ketosis records, Monitor fat-burning status, Track diet and exercise impact

**Features:** macOS Compatibility

**In-app purchases:** none


### MetFix

[App page](https://appshunter.io/ios/app/metfix/id6773266307)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Critical Thinking Courses | $150.00 | one-time |
| Diabetes Course | $150.00 | one-time |
| Fit For Duty Course | $350.00 | one-time |
| MetFix Essentials Course | $500.00 | one-time |


## Frequently asked questions

### Is KetoAir free?

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

### Is MetFix free?

MetFix is free to download, with in-app purchases available.

### Do KetoAir or MetFix have ads?

Neither KetoAir nor MetFix shows ads.

### Which is updated more often, KetoAir or MetFix?

KetoAir ships an update every 2 months, and MetFix every 4 days. Most recently, KetoAir was updated on October 6, 2026 and MetFix on October 22, 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.*