# SlimByte vs BK400

The clearest difference is in-app purchases: BK400 at none against SlimByte's 3. BK400 also leads on update cadence (weekly vs every 5 months) and iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. SlimByte sells 3 in-app purchases, starting at $1.99 per 7 days. BK400 asks for nothing beyond the download.

SlimByte ships an update every 5 months, BK400 weekly. The most recent releases landed on October 28, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | SlimByte | BK400 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 5 months | **Weekly** |
| Size | 15 MB | 21 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Aleksandar Golubovic](https://appshunter.io/developer/1780353102) | [祖策 谢](https://appshunter.io/developer/983519195) |

## What reviewers say

### SlimByte

[App page](https://appshunter.io/ios/app/slimbyte-phone-storage-saver/id6742334573)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Premium | $1.99 | per 7 days |
| Monthly Premium | $2.99 | per month |
| Annual Premium | $29.99 | per year |


### BK400

[App page](https://appshunter.io/ios/app/bk400/id6760681499)

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

**In-app purchases:** none


## Frequently asked questions

### Is SlimByte free?

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

### Is BK400 free?

BK400 is free to download, with no in-app purchases.

### Do SlimByte or BK400 have ads?

Neither SlimByte nor BK400 shows ads.

### Which is updated more often, SlimByte or BK400?

SlimByte ships an update every 5 months, and BK400 weekly. Most recently, SlimByte was updated on October 28, 2026 and BK400 on October 25, 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.*