# SPA Royal Castle vs Virtual Ringelmann

The clearest difference is update cadence: Virtual Ringelmann at monthly against SPA Royal Castle's every 3 months. SPA Royal Castle's advantage is iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

SPA Royal Castle ships an update every 3 months, Virtual Ringelmann monthly. The most recent releases landed on October 17, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | SPA Royal Castle | Virtual Ringelmann |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 50.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | — | Free |
| Size | 76 MB | 73 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Clintec Sistemas](https://appshunter.io/developer/1091785758) | [ACT Sistemas LTDA](https://appshunter.io/developer/1569392578) |

## What reviewers say

### SPA Royal Castle

[App page](https://appshunter.io/ios/app/spa-royal-castle/id1563784309)

**Features:** macOS Compatibility

**In-app purchases:** none


### Virtual Ringelmann

[App page](https://appshunter.io/ios/app/virtual-ringelmann/id1569392576)

This app aids in black smoke inspections by virtualizing the Ringelmann Scale methodology through your device's camera. It streamlines the process for assessing emissions from diesel engines and industrial chimneys, supporting environmental compliance and decision-making.

**Highlights:** Virtual Ringelmann Scale measurement, Supports vehicular and stationary surveillance, Automatic pollution index identification, Generates photographic evidence, Web portal integration for reports, Historical data logging

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SPA Royal Castle free?

SPA Royal Castle is free to download, with no in-app purchases.

### Is Virtual Ringelmann free?

Virtual Ringelmann is free to download, with no in-app purchases.

### Do SPA Royal Castle or Virtual Ringelmann have ads?

Neither SPA Royal Castle nor Virtual Ringelmann shows ads.

### Which is updated more often, SPA Royal Castle or Virtual Ringelmann?

SPA Royal Castle ships an update every 3 months, and Virtual Ringelmann monthly. Most recently, SPA Royal Castle was updated on October 17, 2026 and Virtual Ringelmann on October 15, 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.*