# Hardness Unit Converter

> Converts hardness values between 12 common units using ASTM E 140 standards. (iPhone/iPad app by Kei Suefuji.)

- Source: https://appshunter.io/ios/app/hardness-unit-converter/id1409248484 (this page in markdown: same URL + `.md`)
- Developer: [Kei Suefuji](https://appshunter.io/developer/1388335881)
- Category: Utilities, Productivity
- Price: $1.99
- Rating: 4.00/5 from 7 App Store ratings · 5 written reviews indexed
- Age rating: 4+
- Requires: iOS 12.0 · 8 MB
- Languages: American English, Dutch, Canadian French, German (Germany), Italian, Japanese, Korean, Brazilian Portuguese, Russian, Chinese (Simplified, China) and 4 more
- Released: 2018-07-28
- Data updated: 2026-08-20
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/hardness-unit-converter/id1409248484/reviews.md

## What is Hardness Unit Converter?

The Hardness Unit Converter application converts the hardness into 12 types of units.
The units to be converted by this application are Vickers hardness HV, Brinell hardness HBS, HBW, Rockwell hardness HRA, HRB, HRC, HRD, Rockwell superficial hardness HR 15 N, HR 30 N, HR 45 N, Shore hardness HS, and tensile strength MPa.
Simply input the hardness value and select the unit of hardness with the unit selection button, it will be converted into 12 types of units.
This application refers to the approximate conversion table of ASTM E 140 Table 1 and JIS, and data not in the table is calculated by polynomial approximation.
Values ​​in the range not normally used are indicated by ().

## Key features

- Converts 12 hardness units
- Vickers, Brinell, Rockwell, Shore support
- Tensile strength conversion
- ASTM E 140 reference
- Polynomial approximation for data
- Simple input and unit selection

## Recent user reviews (5 of 5)

All indexed reviews: https://appshunter.io/ios/app/hardness-unit-converter/id1409248484/reviews.md

### 2/5 — Wrong conversion?

*2021-11-30*

So the interface is quite nice.  The conversions aren’t the most accurate, but close.  However, the wheels really come off the bus when conversting Vickers and Rockwell B. The app converts 160 HV to HRB as 81.7 (close), but when you enter 161 HV, it converts it to 116.7, and it gets worse from there.

**Developer response:** Thank you for your advice.
As I confirmed here, it is true that the conversion formulas for Vickers and Rockwell B were wrong. I'm very sorry.
We are planning to release ver2.1.0 with modified conversion formulas for Vickers and Rockwell B in the near future.
We apologize for the inconvenience, but please update the app and check if it has been fixed when it is released.

### 2/5 — 動かない

*2020-06-30*

使えるようになりました。

**Developer response:** ** 更新6/29 **
アップデートしたのに問題が解決せず、大変申し訳ございませんでした。
ダークモードにて、数字が見えなくなっている不具合がわかりました。
至急バージョン2.0.1にアップデートし、表示できるように修正いたしました。
お手数ですが、アプリをアップデートしご確認いただけると幸いです。


** 更新6/28 **
本日、入力部分の不具合等を修正したアップデート版2.0.0をリリースしました。
お手数ですが、本アプリをアップデートして値の入力が可能かご確認ください。
もしそれでも不具合がある場合、可能でしたらiOSのバージョンアップもご検討ください。

** 更新6/22 **
ご連絡ありがとうございます、iOS13.1.3ですね。
また、動作の確認もしていただきありがとうございます。
こちらで不具合が再現できるか確認し、修正方法を検討いたします。
可能であればiPhoneの機種(iPhone 11やiPhone SE)等も教えていただけると幸いです。
しばらくお待ちください。
*************
ダウンロードしていただきありがとうございます。
硬度入力欄をタップしていただき、数字を入力すると各単位に変換した硬度が表示されませんか？例えば380などの値を入力して確認することは可能でしょうか？
もしそれでも動作しないようでしたら、App Storeの本アプリのAppサポートをタップし、お問い合わせフォームにお使いのiPhoneのバージョン等を教えていただけませんか。不具合であれば可能なかぎり修正してアップデートにて対応いたします。
ご迷惑をおかけして申し訳ございませんが、よろしくお願いいたします。

### 1/5 — ใช้งานไม่ได้

*2020-06-16, version 1.1.1*

เสียเงินซื้อมาแล้วใช้งานไม่ได้

### 1/5 — Doesn’t work  don’t use this app

*2019-10-31, version 1.1.0*

add the hardness number  and press convertor  
no effect no any result

### 1/5 — 最悪

*2019-06-25*

正しく換算されない。

**Developer response:** ダウンロードしていただき、ありがとうございます。

現象を検証してアプリを改善していきたいと思いますので、
下記サポートからどのように正しく換算されないのか教えていただけませんか。
https://akikibai-labolatory.jimdofree.com/contact-us/

## Frequently asked questions about Hardness Unit Converter

### What hardness units does Hardness Unit Converter support?

Hardness Unit Converter supports Vickers (HV), Brinell (HBS, HBW), Rockwell (HRA, HRB, HRC, HRD), Rockwell superficial (HR 15 N, HR 30 N, HR 45 N), Shore (HS), and tensile strength (MPa).

### How accurate are the conversions in Hardness Unit Converter?

Conversions reference the approximate conversion table of ASTM E 140 Table 1 and JIS. Data not in the table is calculated by polynomial approximation for accuracy.

### What devices is Hardness Unit Converter available on?

Hardness Unit Converter is available on iPhone, iPad, and iPod devices.

### How much does Hardness Unit Converter cost?

Hardness Unit Converter is a paid application, priced at $1.99.

### When was Hardness Unit Converter last updated?

The latest version of Hardness Unit Converter is 2.5.0, last updated on January 12, 2026.

### What is the age rating for Hardness Unit Converter?

Hardness Unit Converter has an age rating of 4+, making it suitable for a wide range of users.

### Does Hardness Unit Converter have ads?

No, Hardness Unit Converter does not contain advertisements.

### What is the user sentiment for Hardness Unit Converter?

Based on available data, Hardness Unit Converter has a rating of 4.0 stars from 7 ratings, indicating generally positive user sentiment.

## Version history (last 5 releases)

### 2.5.0 — 2026-01-12

Minor improvements.

### 2.4.0 — 2024-07-30

This update supports iOS 17.5.

### 2.3.0 — 2022-02-16

Minor bug fixes

### 2.2.0 — 2022-02-02

Minor improvements

### 2.1.0 — 2021-12-01

Corrected the Rockwell Hardness B Scale (HRB) conversion formula.

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All apps by Kei Suefuji: https://appshunter.io/developer/1388335881

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-20.*