# Math Decoder vs Fettsyrer

The clearest difference is price: Math Decoder at $0.99 against Fettsyrer's $1.99. Math Decoder also leads on iOS requirement (12.0 vs 16.0). On update cadence, ads, in-app purchases and device support there is nothing between them.

Math Decoder costs $0.99 and Fettsyrer $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Math Decoder ships an update every 36 months, Fettsyrer every 25 months. The most recent releases landed on September 20, 2026 and July 23, 2026 respectively.

## The numbers

| Metric | Math Decoder | Fettsyrer |
| --- | --- | --- |
| Price | **$0.99** | $1.99 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 36 months | **Every 25 months** |
| Size | 28 MB | 2 MB |
| Requires iOS | **12.0** | 16.0 |
| Devices | iPad | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Ventura Educational Systems](https://appshunter.io/developer/371324172) | [Torgeir Holen](https://appshunter.io/developer/640499199) |

## What reviewers say

### Math Decoder

[App page](https://appshunter.io/ios/app/math-decoder/id1387526040)

**Features:** macOS Compatibility

**In-app purchases:** none


### Fettsyrer

[App page](https://appshunter.io/ios/app/fettsyrer/id1434524589)

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

**In-app purchases:** none


## Frequently asked questions

### Is Math Decoder free?

Math Decoder costs $0.99, with no in-app purchases.

### Is Fettsyrer free?

Fettsyrer costs $1.99, with no in-app purchases.

### Do Math Decoder or Fettsyrer have ads?

Neither Math Decoder nor Fettsyrer shows ads.

### Which is updated more often, Math Decoder or Fettsyrer?

Math Decoder ships an update every 36 months, and Fettsyrer every 25 months. Most recently, Math Decoder was updated on September 20, 2026 and Fettsyrer on July 23, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*