# CO2 vs VitalGym Köln

The clearest difference is update cadence: VitalGym Köln at every 8 months against CO2's every 15 months. CO2's advantage is iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

CO2 ships an update every 15 months, VitalGym Köln every 8 months. The most recent releases landed on October 6, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | CO2 | VitalGym Köln |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 15 months | **Every 8 months** |
| Size | 39 MB | 210 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Deutsche Gesetzliche Unfallversicherung e.V. (DGUV)](https://appshunter.io/developer/487126969) | [VitalGym Kln Selina Haupt & Julian Herzog GbR](https://appshunter.io/developer/1797501465) |

## What reviewers say

### CO2

[App page](https://appshunter.io/ios/app/co2-timer/id1482287779)

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

**In-app purchases:** none


### VitalGym Köln

[App page](https://appshunter.io/ios/app/vitalgym-koln/id6742224431)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CO2 free?

CO2 is free to download, with no in-app purchases.

### Is VitalGym Köln free?

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

### Do CO2 or VitalGym Köln have ads?

Neither CO2 nor VitalGym Köln shows ads.

### Which is updated more often, CO2 or VitalGym Köln?

CO2 ships an update every 15 months, and VitalGym Köln every 8 months. Most recently, CO2 was updated on October 6, 2026 and VitalGym Köln on October 8, 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.*