# Sub Buddy vs Learn Kotlin

Sub Buddy and Learn Kotlin both sit at 5.0 stars, but that hides the real split: 100% of Sub Buddy's written reviews are positive against 0% of Learn Kotlin's. Sub Buddy also leads on ratings volume (10 vs 1). Learn Kotlin's advantage is price (Free vs $5.99) and update cadence (every 3 months vs every 12 months). On rating, ads, in-app purchases and device support there is nothing between them.

Learn Kotlin is free to download; Sub Buddy costs $5.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for Sub Buddy against 5.0 for Learn Kotlin. That said, the two scores are not equally well evidenced: Sub Buddy has 10 ratings behind it against 1, so its average is the more settled of the two. Written reviews are what separate them: 100% of Sub Buddy's written reviews are positive against 0% of Learn Kotlin's.

Sub Buddy ships an update every 12 months, Learn Kotlin every 3 months. The most recent releases landed on October 12, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Sub Buddy | Learn Kotlin |
| --- | --- | --- |
| Price | $5.99 | **Free** |
| Rating | [5.0 (10 ratings)](https://appshunter.io/ios/app/sub-buddy/id1470196349/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/learn-kotlin-onepercent/id1560955321/reviews) |
| Number of ratings | **10** | 1 |
| Positive reviews | **100.0% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 3 months** |
| Monetization | Paid | **Free** |
| Size | 1.2 GB | 28 MB |
| Requires iOS | 12.0 | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Zoe Summers](https://appshunter.io/developer/1468119556) | [OnePercent](https://appshunter.io/developer/1536020418) |

## What reviewers say

### Sub Buddy

[App page](https://appshunter.io/ios/app/sub-buddy/id1470196349)

This app provides a realistic digital replica of a German U-boat Attack Disc, functioning as a circular slide rule for complex torpedo calculations in WW2 submarine games. It includes 27 training videos and a visual Angle on Bow helper, with customizable controls for left and right-handed users.

**Highlights:** Realistic U-boat Attack Disc simulation, Circular slide rule for torpedo solutions, 27 bundled training videos, Visual Angle on Bow helper, Adjustable time of day and weather, Left and right-handed modes, Customizable menu system

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

**In-app purchases:** none


### Learn Kotlin

[App page](https://appshunter.io/ios/app/learn-kotlin-onepercent/id1560955321)

Master Kotlin programming from beginner to advanced concepts with interactive lessons, quizzes, and demo programs. Prepare for interviews with real Q&A. Available on all platforms for free.

**Highlights:** Comprehensive Kotlin lessons, Interview preparation Q&A, Interactive quizzes, Demo programs for visualization, Clear syntax explanations, Ad-free experience

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Sub Buddy free?

Sub Buddy costs $5.99, with no in-app purchases.

### Is Learn Kotlin free?

Learn Kotlin is free to download, with no in-app purchases.

### Which has better reviews, Sub Buddy or Learn Kotlin?

Sub Buddy and Learn Kotlin are both rated 5.0 out of 5 on the App Store, from 10 and 1 ratings respectively.

### Do Sub Buddy or Learn Kotlin have ads?

Neither Sub Buddy nor Learn Kotlin shows ads.

### Which is updated more often, Sub Buddy or Learn Kotlin?

Sub Buddy ships an update every 12 months, and Learn Kotlin every 3 months. Most recently, Sub Buddy was updated on October 12, 2026 and Learn Kotlin on October 1, 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.*