# Engineering Calculator vs Smart Unit Conversion

The clearest difference is in-app purchases: Engineering Calculator at none against Smart Unit Conversion's 1. Engineering Calculator also leads on update cadence (monthly vs every 15 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Smart Unit Conversion sells 1 in-app purchase, starting at $1.99 per year. Engineering Calculator asks for nothing beyond the download.

Engineering Calculator ships an update monthly, Smart Unit Conversion every 15 months. The most recent releases landed on September 23, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Engineering Calculator | Smart Unit Conversion |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (2 ratings)](https://appshunter.io/ios/app/engineering-calculator/id1395510375/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | **Monthly** | Every 15 months |
| Monetization | Ad-supported | — |
| Size | 1 MB | 41 MB |
| Requires iOS | **12.2** | 13.4 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Masato Kanazawa](https://appshunter.io/developer/1110570349) | [Yui Lau](https://appshunter.io/developer/1791465155) |

## What reviewers say

### Engineering Calculator

[App page](https://appshunter.io/ios/app/engineering-calculator/id1395510375)

This utility app helps users convert units and calculate tips, primarily for those in the US. It operates offline and aims for minimal user interaction to provide quick results. Useful for avoiding misunderstandings in business dealings due to unit differences.

**Highlights:** Unit conversion, Tip calculation, Offline functionality, Minimalist interface, Business negotiation aid

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

**In-app purchases:** none


### Smart Unit Conversion

[App page](https://appshunter.io/ios/app/smart-unit-conversion/id1643381985)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Year | $1.99 | per year |


## Frequently asked questions

### Is Engineering Calculator free?

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

### Is Smart Unit Conversion free?

Smart Unit Conversion is free to download, with in-app purchases available.

### Do Engineering Calculator or Smart Unit Conversion have ads?

Both Engineering Calculator and Smart Unit Conversion show ads.

### Which is updated more often, Engineering Calculator or Smart Unit Conversion?

Engineering Calculator ships an update monthly, and Smart Unit Conversion every 15 months. Most recently, Engineering Calculator was updated on September 23, 2026 and Smart Unit Conversion on October 8, 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.*