# Chemical Engineering Formulate vs rubyi

The clearest difference is review sentiment: rubyi at 82% against Chemical Engineering Formulate's 0%. rubyi also leads on price (Free vs $4.99) and update cadence (every 3 months vs every 8 months). On ads and in-app purchases there is nothing between them.

rubyi is free to download; Chemical Engineering Formulate costs $4.99 up front. Chemical Engineering Formulate sells 1 one-off in-app purchase and rubyi sells 7 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Chemical Engineering Formulate ships an update every 8 months, rubyi every 3 months. Both last shipped on October 23, 2026.

## The numbers

| Metric | Chemical Engineering Formulate | rubyi |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | — | **[4.7 (27 ratings)](https://appshunter.io/ios/app/rubyi-run-code-autocomplete/id581732143/reviews)** |
| Number of ratings | — | **27** |
| Positive reviews | 0.0% of reviews | **81.7% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 3 months** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 19 MB | 45 MB |
| Requires iOS | 18.6 | **14.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 4+ | 17+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [小文 黄](https://appshunter.io/developer/490328393) |

## What reviewers say

### Chemical Engineering Formulate

[App page](https://appshunter.io/ios/app/chemical-engineering-formulate/id354670363)

This comprehensive reference tool provides over 1,500 formulas, calculators, and conversion charts for chemical engineering professionals and students. It covers a wide range of topics including heat transfer, fluid mechanics, and reaction kinetics, with support for both US and Metric units.

**Highlights:** 1,500+ formulas and calculators, 700+ engineering calculators, US/Metric unit toggle, Dual-unit display, Searchable reference tables, Offline functionality, Save and share calculations

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Chemistry Pro | $3.99 | one-time |


### rubyi

[App page](https://appshunter.io/ios/app/rubyi-run-code-autocomplete/id581732143)

Learn, run, and share Ruby scripts with an iOS app offering code completion, syntax highlighting, and a built-in browser. Customize your coding environment and even run code on your Apple Watch.

**Highlights:** Autocomplete, Auto Indent, Code coloring, Run selected text, Apple Watch code execution, Code templates, File system support

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| To remove ads | $0.99 | one-time |
| Password Service | $0.99 | one-time |
| Horizontal screen development | $0.99 | one-time |
| Simple Vedio | $0.99 | one-time |
| Encryption Compression | $0.99 | one-time |
| Text Search | $0.99 | one-time |
| Autocomplete | $0.99 | one-time |


## Frequently asked questions

### Is Chemical Engineering Formulate free?

Chemical Engineering Formulate costs $4.99, and also offers in-app purchases.

### Is rubyi free?

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

### Do Chemical Engineering Formulate or rubyi have ads?

Neither Chemical Engineering Formulate nor rubyi shows ads.

### Which is updated more often, Chemical Engineering Formulate or rubyi?

Chemical Engineering Formulate ships an update every 8 months, and rubyi every 3 months. Most recently, Chemical Engineering Formulate was updated on October 23, 2026 and rubyi on October 23, 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.*