# Diffraction Grating Calculator vs Metal Detector Pro+

The clearest difference is price: Metal Detector Pro+ at Free against Diffraction Grating Calculator's $2.99. Metal Detector Pro+ also leads on update cadence (every 2 months vs every 29 months). Diffraction Grating Calculator's advantage is in-app purchases (none vs 3) and iOS requirement (13 vs 15.0). On ads and device support there is nothing between them.

Metal Detector Pro+ is free to download; Diffraction Grating Calculator costs $2.99 up front. Metal Detector Pro+ sells 3 in-app purchases, starting at $2.99 per 7 days. Diffraction Grating Calculator asks for nothing beyond the download.

Diffraction Grating Calculator ships an update every 29 months, Metal Detector Pro+ every 2 months. The most recent releases landed on September 29, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | Diffraction Grating Calculator | Metal Detector Pro+ |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | — | **[4.6 (36 ratings)](https://appshunter.io/ios/app/metal-detector-pro-plus/id6478103915/reviews)** |
| Number of ratings | — | **36** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 29 months | **Every 2 months** |
| Monetization | — | Free with in-app purchases |
| Size | 1 MB | 5 MB |
| Requires iOS | **13** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [HyperMind Ltd.](https://appshunter.io/developer/1716705401) |

## What reviewers say

### Diffraction Grating Calculator

[App page](https://appshunter.io/ios/app/diffraction-grating-calculator/id1413088894)

**Features:** macOS Compatibility

**In-app purchases:** none


### Metal Detector Pro+

[App page](https://appshunter.io/ios/app/metal-detector-pro-plus/id6478103915)

Detect hidden metallic objects and monitor electromagnetic fields using your device's magnetometer. Ideal for construction, treasure hunting, and health safety by identifying EMF radiation from appliances. Receive alerts for high magnetic fields.

**Highlights:** Detect metallic objects in walls and wood, Monitor EMF radiation from appliances, Receive audible and vibration alerts, View magnetic field measurements, Track detection history, Suitable for treasure hunting

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Premium | $2.99 | per 7 days |
| Monthly Premium | $4.99 | per month |
| Lifetime Access | $8.99 | one-time |


## Frequently asked questions

### Is Diffraction Grating Calculator free?

Diffraction Grating Calculator costs $2.99, with no in-app purchases.

### Is Metal Detector Pro+ free?

Metal Detector Pro+ is free to download, with in-app purchases available.

### Do Diffraction Grating Calculator or Metal Detector Pro+ have ads?

Neither Diffraction Grating Calculator nor Metal Detector Pro+ shows ads.

### Which is updated more often, Diffraction Grating Calculator or Metal Detector Pro+?

Diffraction Grating Calculator ships an update every 29 months, and Metal Detector Pro+ every 2 months. Most recently, Diffraction Grating Calculator was updated on September 29, 2026 and Metal Detector Pro+ on October 7, 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.*