# Smart Unit Conversion vs 一键换算

The clearest difference is in-app purchases: 一键换算 at none against Smart Unit Conversion's 1. 一键换算 also leads on ads (none vs shown) and update cadence (every 4 days vs every 15 months). Smart Unit Conversion's advantage is iOS requirement (13.4 vs 15.0). On price and device support there is nothing between them.

Both are free to download. Smart Unit Conversion sells 1 in-app purchase, starting at $1.99 per year. 一键换算 asks for nothing beyond the download.

Smart Unit Conversion ships an update every 15 months, 一键换算 every 4 days. The most recent releases landed on October 8, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Smart Unit Conversion | 一键换算 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 15 months | **Every 4 days** |
| Size | 41 MB | 0 MB |
| Requires iOS | **13.4** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Yui Lau](https://appshunter.io/developer/1791465155) | [晓明 徐](https://appshunter.io/developer/1030303503) |

## What reviewers say

### 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 |


### 一键换算

[App page](https://appshunter.io/ios/app/id6451350869)

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

**In-app purchases:** none


## Frequently asked questions

### Is Smart Unit Conversion free?

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

### Is 一键换算 free?

一键换算 is free to download, with no in-app purchases.

### Do Smart Unit Conversion or 一键换算 have ads?

Smart Unit Conversion shows ads; 一键换算 does not.

### Which is updated more often, Smart Unit Conversion or 一键换算?

Smart Unit Conversion ships an update every 15 months, and 一键换算 every 4 days. Most recently, Smart Unit Conversion was updated on October 8, 2026 and 一键换算 on October 6, 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.*