# N'Back Butterfly vs GridLock Numbers

The clearest difference is in-app purchases: N'Back Butterfly at none against GridLock Numbers's 4. GridLock Numbers's advantage is ads (none vs shown) and update cadence (every 6 weeks vs every 10 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. GridLock Numbers sells 4 one-off in-app purchases. N'Back Butterfly asks for nothing beyond the download.

N'Back Butterfly ships an update every 10 months, GridLock Numbers every 6 weeks. The most recent releases landed on August 31, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | N'Back Butterfly | GridLock Numbers |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 10 months | **Every 6 weeks** |
| Monetization | Ad-supported | — |
| Size | 9 MB | 5 MB |
| Requires iOS | **15.6** | 16.2 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Yasuyoshi Ota](https://appshunter.io/developer/1500357652) | [Aycan YILMAZ](https://appshunter.io/developer/912871298) |

## What reviewers say

### N'Back Butterfly

[App page](https://appshunter.io/ios/app/nback-butterfly/id853507894)

Enhance your cognitive abilities and combat forgetfulness with this application designed to improve working memory. It utilizes the scientifically recognized n-back task to train your brain's capacity for information recall and manipulation.

**Highlights:** Working memory improvement, N-back task training, Cognitive neuroscience assessment, Continuous performance task

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

**In-app purchases:** none


### GridLock Numbers

[App page](https://appshunter.io/ios/app/gridlock-numbers/id912871295)

**Features:** macOS Compatibility

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pack of 10 Crowns | $0.99 | one-time |
| Pack of 30 Crowns | $1.99 | one-time |
| Pack of 60 Crowns | $2.99 | one-time |
| Pack of 120 Crowns | $3.99 | one-time |


## Frequently asked questions

### Is N'Back Butterfly free?

N'Back Butterfly is free to download, with no in-app purchases.

### Is GridLock Numbers free?

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

### Do N'Back Butterfly or GridLock Numbers have ads?

N'Back Butterfly shows ads; GridLock Numbers does not.

### Which is updated more often, N'Back Butterfly or GridLock Numbers?

N'Back Butterfly ships an update every 10 months, and GridLock Numbers every 6 weeks. Most recently, N'Back Butterfly was updated on August 31, 2026 and GridLock Numbers on September 7, 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.*