# Klaus vs CPianoS

The clearest difference is in-app purchases: Klaus at none against CPianoS's 2. Klaus also leads on ads (none vs shown) and iOS requirement (12.0 vs 26.0). CPianoS's advantage is update cadence (every 3 days vs monthly). On price and device support there is nothing between them.

Both are free to download. CPianoS sells 2 in-app purchases, starting at $5.49 per month. Klaus asks for nothing beyond the download.

Klaus ships an update monthly, CPianoS every 3 days. The most recent releases landed on November 5, 2026 and November 10, 2026 respectively.

## The numbers

| Metric | Klaus | CPianoS |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Monthly | **Every 3 days** |
| Size | 32 MB | 118 MB |
| Requires iOS | **12.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Markus Stradner](https://appshunter.io/developer/1884693633) | [Miyauchi Isao](https://appshunter.io/developer/1886398515) |

## What reviewers say

### Klaus

[App page](https://appshunter.io/ios/app/klaus-die-hackbrett-maus/id6760487536)

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

**In-app purchases:** none


### CPianoS

[App page](https://appshunter.io/ios/app/cpianos/id6818919453)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium (Monthly) | $5.49 | per month |
| Premium (Yearly) | $46.99 | per year |


## Frequently asked questions

### Is Klaus free?

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

### Is CPianoS free?

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

### Do Klaus or CPianoS have ads?

CPianoS shows ads; Klaus does not.

### Which is updated more often, Klaus or CPianoS?

Klaus ships an update monthly, and CPianoS every 3 days. Most recently, Klaus was updated on November 5, 2026 and CPianoS on November 10, 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.*