# PhysKey Custom vs Derivon

The clearest difference is in-app purchases: PhysKey Custom at none against Derivon's 5. PhysKey Custom also leads on ads (none vs shown) and iOS requirement (16.0 vs 26.0). Derivon's advantage is update cadence (every 5 days vs every 4 months). On price and device support there is nothing between them.

Both are free to download. Derivon sells 5 in-app purchases, starting at $1.99 per month. PhysKey Custom asks for nothing beyond the download.

PhysKey Custom ships an update every 4 months, Derivon every 5 days. The most recent releases landed on October 31, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | PhysKey Custom | Derivon |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (1 ratings)](https://appshunter.io/ios/app/derivon-calculus-practice/id6761150220/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 4 months | **Every 5 days** |
| Monetization | — | Free with in-app purchases |
| Size | 5 MB | 206 MB |
| Requires iOS | **16.0** | 26.0 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Ryosuke Asano](https://appshunter.io/developer/1858758761) | [ABT合同会社](https://appshunter.io/developer/6813846553) |

## What reviewers say

### PhysKey Custom

[App page](https://appshunter.io/ios/app/physkey-custom/id6757507136)

**In-app purchases:** none


### Derivon

[App page](https://appshunter.io/ios/app/derivon-calculus-practice/id6761150220)

Master calculus concepts like derivatives and integrals through daily, intuitive practice. Earn rewards, collect planets, and build streaks as you progress through challenges. Designed for quick, effective learning sessions.

**Highlights:** Daily calculus problem practice, Earn Star Sand rewards, Collect planets in Gallery, Build and maintain daily streaks, Rank-Up Challenges, Shooting mode for breaks

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Derivon Super (Monthly) | $1.99 | per month |
| Derivon Super (Yearly) | $14.99 | per year |
| 5 Star Fragments | $0.99 | one-time |
| 12 Star Fragments | $1.99 | one-time |
| 32 Star Fragments | $3.99 | one-time |


## Frequently asked questions

### Is PhysKey Custom free?

PhysKey Custom is free to download, with no in-app purchases.

### Is Derivon free?

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

### Do PhysKey Custom or Derivon have ads?

Derivon shows ads; PhysKey Custom does not.

### Which is updated more often, PhysKey Custom or Derivon?

PhysKey Custom ships an update every 4 months, and Derivon every 5 days. Most recently, PhysKey Custom was updated on October 31, 2026 and Derivon on October 28, 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.*