# Cerebrum ID vs K

The clearest difference is price: K at Free against Cerebrum ID's $4.99. K also leads on update cadence (every 14 months vs every 37 months) and iOS requirement (8.0 vs 11.0). Cerebrum ID's advantage is device support (3 vs 1). On ads and in-app purchases there is nothing between them.

K is free to download; Cerebrum ID costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Cerebrum ID ships an update every 37 months, K every 14 months. The most recent releases landed on November 11, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Cerebrum ID | K |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/k-d-test-pro-reading/id1068456746/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 37 months | **Every 14 months** |
| Monetization | — | Free |
| Size | 23 MB | 57 MB |
| Requires iOS | 11.0 | **8.0** |
| Devices | **iPhone, iPad, iPod** | iPad |
| Age rating | 4+ | 12+ |
| Developer | [Blue Tree Publishing, Inc.](https://appshunter.io/developer/496143325) | [King-Devick Test, LLC](https://appshunter.io/developer/424793545) |

## What reviewers say

### Cerebrum ID

[App page](https://appshunter.io/ios/app/cerebrum-id/id916296922)

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

**In-app purchases:** none


### K

[App page](https://appshunter.io/ios/app/k-d-test-pro-reading/id1068456746)

This application facilitates the administration of a rapid eye movement test for reading assessment. It compares performance against age-related norms for individuals aged 6-14+, helping to identify potential candidates for reading intervention programs.

**Highlights:** Reads numbers from test cards, Measures speed and accuracy, Compares results to age norms, Identifies candidates for intervention, Administered in under two minutes, Validated by peer-reviewed studies

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Cerebrum ID free?

Cerebrum ID costs $4.99, with no in-app purchases.

### Is K free?

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

### Do Cerebrum ID or K have ads?

Neither Cerebrum ID nor K shows ads.

### Which is updated more often, Cerebrum ID or K?

Cerebrum ID ships an update every 37 months, and K every 14 months. Most recently, Cerebrum ID was updated on November 11, 2026 and K on November 2, 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.*