# NDT Worldwide vs Liquid Penetrant Study Guide

The clearest difference is price: NDT Worldwide at Free against Liquid Penetrant Study Guide's $14.99. NDT Worldwide also leads on iOS requirement (15.6 vs 18.5). Liquid Penetrant Study Guide's advantage is in-app purchases (none vs 10) and update cadence (every 3 months vs every 16 months). On ads and device support there is nothing between them.

NDT Worldwide is free to download; Liquid Penetrant Study Guide costs $14.99 up front. NDT Worldwide sells 10 one-off in-app purchases. Liquid Penetrant Study Guide asks for nothing beyond the download.

NDT Worldwide ships an update every 16 months, Liquid Penetrant Study Guide every 3 months. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | NDT Worldwide | Liquid Penetrant Study Guide |
| --- | --- | --- |
| Price | **Free** | $14.99 |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 16 months | **Every 3 months** |
| Size | 265 MB | 2 MB |
| Requires iOS | **15.6** | 18.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [WWNDT SERVICES PRIVATE LIMITED](https://appshunter.io/developer/1570208273) | [Skaggs Media LLC](https://appshunter.io/developer/1836684180) |

## What reviewers say

### NDT Worldwide

[App page](https://appshunter.io/ios/app/ndt-worldwide/id1607234047)

**Features:** macOS Compatibility, Apple Wallet

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ASTM E165 | $44.99 | one-time |
| ASTM E2582 | $44.99 | one-time |
| ASTM E2375 | $54.99 | one-time |
| ASTM E709 | $54.99 | one-time |
| ASTM E2375 | $69.99 | one-time |
| ASNT MT Level III Examination | $219.99 | one-time |
| ASNT NDT Level III-BASIC | $299.99 | one-time |
| ASNT UT Level III Examination | $299.99 | one-time |
| ASNT ML Level III Examination | $399.99 | one-time |
| ASNT NDT Level III BASIC | $449.99 | one-time |


### Liquid Penetrant Study Guide

[App page](https://appshunter.io/ios/app/liquid-penetrant-study-guide/id6752206188)

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

**In-app purchases:** none


## Frequently asked questions

### Is NDT Worldwide free?

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

### Is Liquid Penetrant Study Guide free?

Liquid Penetrant Study Guide costs $14.99, with no in-app purchases.

### Do NDT Worldwide or Liquid Penetrant Study Guide have ads?

Neither NDT Worldwide nor Liquid Penetrant Study Guide shows ads.

### Which is updated more often, NDT Worldwide or Liquid Penetrant Study Guide?

NDT Worldwide ships an update every 16 months, and Liquid Penetrant Study Guide every 3 months. Most recently, NDT Worldwide was updated on October 25, 2026 and Liquid Penetrant Study Guide on October 24, 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.*