# Chapter vs Engineering Formulas

The clearest difference is in-app purchases: Chapter at none against Engineering Formulas's 3. Chapter also leads on update cadence (every 2 days vs every 2 months). Engineering Formulas's advantage is iOS requirement (15.1 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. Engineering Formulas sells 3 in-app purchases, starting at $4.99 per 7 days. Chapter asks for nothing beyond the download.

Chapter ships an update every 2 days, Engineering Formulas every 2 months. The most recent releases landed on October 30, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Chapter | Engineering Formulas |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 2 months |
| Size | 402 MB | 45 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Chapter Technologies Limited](https://appshunter.io/developer/1756532171) | [Mobin Akhter](https://appshunter.io/developer/1812505286) |

## What reviewers say

### Chapter

[App page](https://appshunter.io/ios/app/chapter-careers-game/id6529547618)

**Features:** macOS Compatibility

**In-app purchases:** none


### Engineering Formulas

[App page](https://appshunter.io/ios/app/engineering-formulas-engiref/id6758258119)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Premium | $4.99 | per 7 days |
| Yearly Premium | $29.99 | per year |
| Lifetime Access | $54.99 | one-time |


## Frequently asked questions

### Is Chapter free?

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

### Is Engineering Formulas free?

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

### Do Chapter or Engineering Formulas have ads?

Neither Chapter nor Engineering Formulas shows ads.

### Which is updated more often, Chapter or Engineering Formulas?

Chapter ships an update every 2 days, and Engineering Formulas every 2 months. Most recently, Chapter was updated on October 30, 2026 and Engineering Formulas on October 25, 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.*