# Size test vs NBack³

The clearest difference is price: NBack³ at Free against Size test's $0.99. NBack³ also leads on update cadence (every 4 days vs every 10 months). Size test's advantage is in-app purchases (none vs 1) and ads (none vs shown). On device support there is nothing between them.

NBack³ is free to download; Size test costs $0.99 up front. NBack³ sells 1 in-app purchase, starting at $0.49 per month. Size test asks for nothing beyond the download.

Size test ships an update every 10 months, NBack³ every 4 days. The most recent releases landed on October 29, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | Size test | NBack³ |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Positive reviews | — | 71.4% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 10 months | **Every 4 days** |
| Monetization | — | Free with in-app purchases |
| Size | 1 MB | 20 MB |
| Requires iOS | **14.0** | 17.0 |
| Devices | iPad | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Viacheslav Romanenko](https://appshunter.io/developer/1046372418) | [Taiki Nishimura](https://appshunter.io/developer/1780302048) |

## What reviewers say

### Size test

[App page](https://appshunter.io/ios/app/size-test/id1059703529)

**In-app purchases:** none


### NBack³

[App page](https://appshunter.io/ios/app/nback-memory-training-game/id6745750227)

This brain training app uses the scientifically proven Dual N-Back method to enhance cognitive functions like working memory, focus, and decision-making. It offers adjustable difficulty levels and tracks progress with a visually engaging interface.

**Highlights:** Dual N-Back method, Adjustable difficulty (n=1-5), Enhances working memory, Improves inhibitory control, Develops attention skills, Progress tracking, Streak bonus system

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| プレミアムプラン | $0.49 | per month |


## Frequently asked questions

### Is Size test free?

Size test costs $0.99, with no in-app purchases.

### Is NBack³ free?

NBack³ is free to download, with in-app purchases available.

### Do Size test or NBack³ have ads?

NBack³ shows ads; Size test does not.

### Which is updated more often, Size test or NBack³?

Size test ships an update every 10 months, and NBack³ every 4 days. Most recently, Size test was updated on October 29, 2026 and NBack³ on November 5, 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.*