# QuaternionCalc vs Tredecuple Calc

The clearest difference is price: Tredecuple Calc at Free against QuaternionCalc's $2.99. Tredecuple Calc also leads on update cadence (every 2 weeks vs every 15 months) and iOS requirement (15.8.3 vs 18.0). QuaternionCalc's advantage is ads (none vs shown). On in-app purchases and device support there is nothing between them.

Tredecuple Calc is free to download; QuaternionCalc costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

QuaternionCalc ships an update every 15 months, Tredecuple Calc every 2 weeks. The most recent releases landed on October 12, 2026 and July 31, 2026 respectively.

## The numbers

| Metric | QuaternionCalc | Tredecuple Calc |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 15 months | **Every 2 weeks** |
| Size | 2 MB | 36 MB |
| Requires iOS | 18.0 | **15.8.3** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Princeton Satellite Systems](https://appshunter.io/developer/395066089) | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) |

## What reviewers say

### QuaternionCalc

[App page](https://appshunter.io/ios/app/quaternioncalc/id1022679681)

**Features:** macOS Compatibility

**In-app purchases:** none


### Tredecuple Calc

[App page](https://appshunter.io/ios/app/tredecuple-calc/id6742305124)

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

**In-app purchases:** none


## Frequently asked questions

### Is QuaternionCalc free?

QuaternionCalc costs $2.99, with no in-app purchases.

### Is Tredecuple Calc free?

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

### Do QuaternionCalc or Tredecuple Calc have ads?

Tredecuple Calc shows ads; QuaternionCalc does not.

### Which is updated more often, QuaternionCalc or Tredecuple Calc?

QuaternionCalc ships an update every 15 months, and Tredecuple Calc every 2 weeks. Most recently, QuaternionCalc was updated on October 12, 2026 and Tredecuple Calc on July 31, 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.*