# Plan 9 vs Sarrus Calculator Matrix Det

The clearest difference is in-app purchases: Plan 9 at none against Sarrus Calculator Matrix Det's 2. Plan 9 also leads on ads (none vs shown). Sarrus Calculator Matrix Det's advantage is update cadence (every 2 months vs every 24 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Sarrus Calculator Matrix Det sells 2 in-app purchases, starting at $4.99 per 7 days. Plan 9 asks for nothing beyond the download.

Plan 9 ships an update every 24 months, Sarrus Calculator Matrix Det every 2 months. The most recent releases landed on October 27, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Plan 9 | Sarrus Calculator Matrix Det |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 24 months | **Every 2 months** |
| Size | 1 MB | 144 MB |
| Requires iOS | **14.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Paul Evenblij](https://appshunter.io/developer/286569767) | [Juan Antonio Veloz Gutierrez](https://appshunter.io/developer/1810351183) |

## What reviewers say

### Plan 9

[App page](https://appshunter.io/ios/app/plan-9/id1510227252)

**In-app purchases:** none


### Sarrus Calculator Matrix Det

[App page](https://appshunter.io/ios/app/sarrus-calculator-matrix-det/id6745130843)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PRO Sarrus Calculator Weekly | $4.99 | per 7 days |
| PRO Sarrus Calculator Yearly | $24.99 | per year |


## Frequently asked questions

### Is Plan 9 free?

Plan 9 is free to download, with no in-app purchases.

### Is Sarrus Calculator Matrix Det free?

Sarrus Calculator Matrix Det is free to download, with in-app purchases available.

### Do Plan 9 or Sarrus Calculator Matrix Det have ads?

Sarrus Calculator Matrix Det shows ads; Plan 9 does not.

### Which is updated more often, Plan 9 or Sarrus Calculator Matrix Det?

Plan 9 ships an update every 24 months, and Sarrus Calculator Matrix Det every 2 months. Most recently, Plan 9 was updated on October 27, 2026 and Sarrus Calculator Matrix Det on October 28, 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.*