# Stack Trainer vs Ruler with Caliper, Protractor

The clearest difference is price: Ruler with Caliper, Protractor at Free against Stack Trainer's $3.99. Stack Trainer's advantage is ads (none vs shown) and update cadence (every 3 months vs every 28 months). On review sentiment, in-app purchases, device support and iOS requirement there is nothing between them.

Ruler with Caliper, Protractor is free to download; Stack Trainer costs $3.99 up front. Stack Trainer sells 2 in-app purchases, starting at $1.99 per 3 months and Ruler with Caliper, Protractor sells 3 in-app purchases, starting at $3.99 per 7 days. Whichever you choose, the download price is not the number that matters.

Stack Trainer ships an update every 3 months, Ruler with Caliper, Protractor every 28 months. The most recent releases landed on October 7, 2026 and October 22, 2026 respectively.

## The numbers

| Metric | Stack Trainer | Ruler with Caliper, Protractor |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/stack-trainer/id646458442/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | 0.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 3 months** | Every 28 months |
| Monetization | Subscription | **Free with in-app purchases** |
| Size | 6 MB | 6 MB |
| Requires iOS | **15.6** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Ralph Cos](https://appshunter.io/developer/573505028) | [Bhavinkumar Satashiya](https://appshunter.io/developer/1361485921) |

## What reviewers say

### Stack Trainer

[App page](https://appshunter.io/ios/app/stack-trainer/id646458442)

This app provides a realistic card deck experience for close-up magicians to train their memory of card stacks. It offers various challenge modes and filters to aid learning and practice, with a focus on a clean, distraction-free interface.

**Highlights:** Realistic card deck simulation, Multiple mnemonic training approaches, Customizable stack filters, Lorrayne's peg words integration, Interactive quick-touch analyzer, Display and whisper modes

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 3 Months Subscription | $1.99 | per 3 months |
| Annual Subscription | $2.99 | per year |


### Ruler with Caliper, Protractor

[App page](https://appshunter.io/ios/app/ruler-with-caliper-protractor/id1368462815)

This app transforms your device into a precise digital measuring tool. It offers accurate measurements for various objects and distances using your camera, with multiple units and offline functionality.

**Highlights:** Accurate measurements via camera, Measure small objects to large distances, User-friendly interface, Multiple measurement units (inches, cm), Virtual ruler on screen, Save and share measurements, Offline accessibility

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly | $3.99 | per 7 days |
| Yearly | $39.99 | per year |
| Lifetime | $49.99 | one-time |


## Frequently asked questions

### Is Stack Trainer free?

Stack Trainer costs $3.99, and also offers in-app purchases.

### Is Ruler with Caliper, Protractor free?

Ruler with Caliper, Protractor is free to download, with in-app purchases available.

### Do Stack Trainer or Ruler with Caliper, Protractor have ads?

Ruler with Caliper, Protractor shows ads; Stack Trainer does not.

### Which is updated more often, Stack Trainer or Ruler with Caliper, Protractor?

Stack Trainer ships an update every 3 months, and Ruler with Caliper, Protractor every 28 months. Most recently, Stack Trainer was updated on October 7, 2026 and Ruler with Caliper, Protractor on October 22, 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.*