# US Unit Converter vs Smart Unit Conversion

The clearest difference is update cadence: US Unit Converter at every 6 months against Smart Unit Conversion's every 15 months. Smart Unit Conversion's advantage is iOS requirement (13.4 vs 15.6). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. US Unit Converter 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.

US Unit Converter ships an update every 6 months, Smart Unit Conversion every 15 months. The most recent releases landed on October 14, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | US Unit Converter | Smart Unit Conversion |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (109 ratings)](https://appshunter.io/ios/app/us-unit-converter/id1577905442/reviews)** | — |
| Number of ratings | **109** | — |
| Positive reviews | 44.4% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 6 months** | Every 15 months |
| Monetization | Free with in-app purchases | — |
| Size | 6 MB | 41 MB |
| Requires iOS | 15.6 | **13.4** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Kei Suefuji](https://appshunter.io/developer/1388335881) | [Yui Lau](https://appshunter.io/developer/1791465155) |

## What reviewers say

### US Unit Converter

[App page](https://appshunter.io/ios/app/us-unit-converter/id1577905442)

Easily convert between US customary units and the International System of Units for various measurements like length, weight, area, volume, and temperature. Access conversion history and remove ads with a premium upgrade.

**Highlights:** Length conversion, Weight conversion, Area conversion, Liquid volume conversion, Temperature conversion, Conversion history, Ad-free option

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PREMIUM | $3.99 | one-time |


### 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 US Unit Converter free?

US Unit Converter 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 US Unit Converter or Smart Unit Conversion have ads?

Both US Unit Converter and Smart Unit Conversion show ads.

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

US Unit Converter ships an update every 6 months, and Smart Unit Conversion every 15 months. Most recently, US Unit Converter was updated on October 14, 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.*