# Hardness Conversion Master vs NDT Master

The clearest difference is ads: NDT Master at none against Hardness Conversion Master's shown. NDT Master also leads on iOS requirement (15 vs 17.6). Hardness Conversion Master's advantage is update cadence (every 3 days vs every 2 weeks). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Hardness Conversion Master sells 1 one-off in-app purchase and NDT Master sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Hardness Conversion Master ships an update every 3 days, NDT Master every 2 weeks. The most recent releases landed on October 22, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Hardness Conversion Master | NDT Master |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (2 ratings)](https://appshunter.io/ios/app/ndt-master-ut-weld-calculator/id6762549446/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Every 2 weeks |
| Monetization | — | Free with in-app purchases |
| Size | 259 MB | 20 MB |
| Requires iOS | 17.6 | **15** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [POYU WANG](https://appshunter.io/developer/1883764660) | [雪 蔺](https://appshunter.io/developer/1853712836) |

## What reviewers say

### Hardness Conversion Master

[App page](https://appshunter.io/ios/app/hardness-conversion-master/id6760411989)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock Pro | $1.99 | one-time |


### NDT Master

[App page](https://appshunter.io/ios/app/ndt-master-ut-weld-calculator/id6762549446)

This app streamlines ultrasonic testing for field inspections. It offers rapid weld rating, DAC/TCG curve building, 3D beam simulation, and OCR parameter capture. Includes essential UT calculators and material presets for efficient flaw detection and setup confidence.

**Highlights:** AWS D-Rating in 5 Seconds, DAC/TCG Curve Building, 3D Beam Simulation, OCR Parameter Capture, 9 UT Calculators, Offline-First Workflow

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Professional Unlock | $9.99 | one-time |


## Frequently asked questions

### Is Hardness Conversion Master free?

Hardness Conversion Master is free to download, with in-app purchases available.

### Is NDT Master free?

NDT Master is free to download, with in-app purchases available.

### Do Hardness Conversion Master or NDT Master have ads?

Hardness Conversion Master shows ads; NDT Master does not.

### Which is updated more often, Hardness Conversion Master or NDT Master?

Hardness Conversion Master ships an update every 3 days, and NDT Master every 2 weeks. Most recently, Hardness Conversion Master was updated on October 22, 2026 and NDT Master on October 25, 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.*