# Sauerstoffrechner vs RetterTool

The clearest difference is in-app purchases: Sauerstoffrechner at none against RetterTool's 5. Sauerstoffrechner also leads on iOS requirement (15.0 vs 17.6). RetterTool's advantage is update cadence (every 2 months vs every 25 months). On price, ads and device support there is nothing between them.

Both are free to download. RetterTool sells 5 in-app purchases, starting at $0.99 per month. Sauerstoffrechner asks for nothing beyond the download.

Sauerstoffrechner ships an update every 25 months, RetterTool every 2 months. The most recent releases landed on October 29, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | Sauerstoffrechner | RetterTool |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 91.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 25 months | **Every 2 months** |
| Monetization | — | Free with in-app purchases |
| Size | 1 MB | 19 MB |
| Requires iOS | **15.0** | 17.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 17+ |
| Developer | [Beate Boehme](https://appshunter.io/developer/595186948) | [8devs GmbH](https://appshunter.io/developer/1517839277) |

## What reviewers say

### Sauerstoffrechner

[App page](https://appshunter.io/ios/app/sauerstoffrechner/id625770232)

**Features:** Vision Pro support

**In-app purchases:** none


### RetterTool

[App page](https://appshunter.io/ios/app/rettertool/id1605575736)

This app provides quick access to essential medical information and calculations for emergency and medical personnel. It includes tools for vital sign measurement, scoring systems, and various medical formulas to aid in patient assessment and treatment.

**Highlights:** Vital sign calculation (heart rate, respiratory rate), Medical scoring systems (qSOFA, APGAR, LAMS, GCS), Memory aids for protocols (ABCDE, SAMPLERS, ISBAR), Formula collection (burns, blood pressure, oxygen), Interactive EKG interpretation tool, Patient age-specific standard values

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro-Version Monatlich | $0.99 | per month |
| Kleines Trinkgeld | $0.99 | one-time |
| Mittleres Trinkgeld | $3.99 | one-time |
| Großes Trinkgeld | $8.99 | one-time |
| Pro-Version Lifetime | $22.99 | one-time |


## Frequently asked questions

### Is Sauerstoffrechner free?

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

### Is RetterTool free?

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

### Do Sauerstoffrechner or RetterTool have ads?

Neither Sauerstoffrechner nor RetterTool shows ads.

### Which is updated more often, Sauerstoffrechner or RetterTool?

Sauerstoffrechner ships an update every 25 months, and RetterTool every 2 months. Most recently, Sauerstoffrechner was updated on October 29, 2026 and RetterTool on October 30, 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.*