# Onikeisan vs NBackCalc

The clearest difference is in-app purchases: Onikeisan at none against NBackCalc's 1. Onikeisan also leads on iOS requirement (12.0 vs 17.0). NBackCalc's advantage is update cadence (every 2 days vs every 9 days). On price, ads and device support there is nothing between them.

Both are free to download. NBackCalc sells 1 one-off in-app purchase. Onikeisan asks for nothing beyond the download.

Onikeisan ships an update every 9 days, NBackCalc every 2 days. The most recent releases landed on October 10, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | Onikeisan | NBackCalc |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 9 days | **Every 2 days** |
| Size | 37 MB | 1 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [iori kojima](https://appshunter.io/developer/1493044568) | [YOSHINORI KONNO](https://appshunter.io/developer/1883074860) |

## What reviewers say

### Onikeisan

[App page](https://appshunter.io/ios/app/onikeisan-n-back/id6745093026)

**Features:** macOS Compatibility

**In-app purchases:** none


### NBackCalc

[App page](https://appshunter.io/ios/app/nbackcalc-working-memory/id6760832395)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 開発者を応援する | $0.99 | one-time |


## Frequently asked questions

### Is Onikeisan free?

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

### Is NBackCalc free?

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

### Do Onikeisan or NBackCalc have ads?

Neither Onikeisan nor NBackCalc shows ads.

### Which is updated more often, Onikeisan or NBackCalc?

Onikeisan ships an update every 9 days, and NBackCalc every 2 days. Most recently, Onikeisan was updated on October 10, 2026 and NBackCalc on October 17, 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.*