# UnitConverter byNSDev vs US Unit Converter

The clearest difference is in-app purchases: UnitConverter byNSDev at none against US Unit Converter's 1. UnitConverter byNSDev also leads on ads (none vs shown). US Unit Converter's advantage is review sentiment (44% vs 20%). On price, update cadence, device support and iOS requirement there is nothing between them.

Both are free to download. US Unit Converter sells 1 one-off in-app purchase. UnitConverter byNSDev asks for nothing beyond the download.

UnitConverter byNSDev ships an update every 5 months, US Unit Converter every 6 months. The most recent releases landed on September 17, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | UnitConverter byNSDev | US Unit Converter |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.8 (108 ratings)](https://appshunter.io/ios/app/us-unit-converter/id1577905442/reviews)** |
| Number of ratings | — | **108** |
| Positive reviews | 20.0% of reviews | **44.4% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 5 months** | Every 6 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 4 MB | 6 MB |
| Requires iOS | 15.6 | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [NIHON SYSTEM DEVELOPER CORPORATION](https://appshunter.io/developer/1198103734) | [Kei Suefuji](https://appshunter.io/developer/1388335881) |

## What reviewers say

### UnitConverter byNSDev

[App page](https://appshunter.io/ios/app/unitconverter-bynsdev/id1229121492)

This tool converts between 26 different types of units, displaying conversion rates and allowing you to specify decimal places. It supports a vast array of units across categories like length, mass, volume, and more.

**Highlights:** Converts 26 types of units, Displays conversion rates, Customizable decimal places, Supports numerous units in various categories, User-submitted unit requests

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

**In-app purchases:** none


### 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 |


## Frequently asked questions

### Is UnitConverter byNSDev free?

UnitConverter byNSDev is free to download, with no in-app purchases.

### Is US Unit Converter free?

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

### Do UnitConverter byNSDev or US Unit Converter have ads?

US Unit Converter shows ads; UnitConverter byNSDev does not.

### Which is updated more often, UnitConverter byNSDev or US Unit Converter?

UnitConverter byNSDev ships an update every 5 months, and US Unit Converter every 6 months. Most recently, UnitConverter byNSDev was updated on September 17, 2026 and US Unit Converter on September 22, 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.*