# Smart Unit Conversion vs Polytron EV 4W

The clearest difference is in-app purchases: Polytron EV 4W at none against Smart Unit Conversion's 1. Polytron EV 4W also leads on ads (none vs shown) and update cadence (every 3 months 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. Polytron EV 4W asks for nothing beyond the download.

Smart Unit Conversion ships an update every 15 months, Polytron EV 4W every 3 months. The most recent releases landed on May 16, 2026 and September 12, 2026 respectively.

## The numbers

| Metric | Smart Unit Conversion | Polytron EV 4W |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 15 months | **Every 3 months** |
| Size | 41 MB | 70 MB |
| Requires iOS | **13.4** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 17+ |
| Developer | [Yui Lau](https://appshunter.io/developer/1791465155) | [My CTRL](https://appshunter.io/developer/1685816257) |

## 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 |


### Polytron EV 4W

[App page](https://appshunter.io/ios/app/polytron-ev-4w/id6751181761)

**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 Polytron EV 4W free?

Polytron EV 4W is free to download, with no in-app purchases.

### Do Smart Unit Conversion or Polytron EV 4W have ads?

Smart Unit Conversion shows ads; Polytron EV 4W does not.

### Which is updated more often, Smart Unit Conversion or Polytron EV 4W?

Smart Unit Conversion ships an update every 15 months, and Polytron EV 4W every 3 months. Most recently, Smart Unit Conversion was updated on May 16, 2026 and Polytron EV 4W on September 12, 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.*