# Unit Converter HD. vs Smart Unit Conversion

The clearest difference is update cadence: Unit Converter HD. at every 2 months against Smart Unit Conversion's every 15 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Unit Converter HD. sells 1 one-off in-app purchase and Smart Unit Conversion sells 1 in-app purchase, starting at $1.99 per year. Whichever you choose, the download price is not the number that matters.

Unit Converter HD. ships an update every 2 months, Smart Unit Conversion every 15 months. The most recent releases landed on September 19, 2026 and May 16, 2026 respectively.

## The numbers

| Metric | Unit Converter HD. | Smart Unit Conversion |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (645 ratings)](https://appshunter.io/ios/app/unit-converter-hd/id481973377/reviews)** | — |
| Number of ratings | **645** | — |
| Positive reviews | 93.8% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 2 months** | Every 15 months |
| Monetization | Free with in-app purchases | — |
| Size | 86 MB | 41 MB |
| Requires iOS | **13.0** | 13.4 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [良峰 侯](https://appshunter.io/developer/654444245) | [Yui Lau](https://appshunter.io/developer/1791465155) |

## What reviewers say

### Unit Converter HD.

[App page](https://appshunter.io/ios/app/unit-converter-hd/id481973377)

Easily convert over 700 units across 30 categories with this powerful tool. It offers a user-friendly interface, dark mode support, and a backspace key for quick corrections. Save time on all your measurement conversion needs.

**Highlights:** 700+ Units of Measure, 30 Conversion Categories, Easy-to-Use Interface, Dark Mode Support, Backspace Key

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads Pack | $1.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 🚀 Handy and convenient
- 💡 Comprehensive set of conversions
- 🚀 Very useful app
- 👍 Intuitive design

**What reviewers complain about**

- 🐛 Occasional crashes or freezing issues
- 💡 Could be more intuitive for some users
- 🔒 Requires horizontal orientation

**Reported bugs**

- Freezing or crashing on some devices
- Display issues with certain units

**Requested features**

- Add support for US weights (tons, lbs., oz.)
- Implement portrait mode support
- Provide more customization options


### 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 Unit Converter HD. free?

Unit Converter HD. is free to download, with in-app purchases available.

### Is Smart Unit Conversion free?

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

### Do Unit Converter HD. or Smart Unit Conversion have ads?

Both Unit Converter HD. and Smart Unit Conversion show ads.

### Which is updated more often, Unit Converter HD. or Smart Unit Conversion?

Unit Converter HD. ships an update every 2 months, and Smart Unit Conversion every 15 months. Most recently, Unit Converter HD. was updated on September 19, 2026 and Smart Unit Conversion on May 16, 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.*