# Biological clock vs 鏡文字の逆読みONLINE

The clearest difference is update cadence: 鏡文字の逆読みONLINE at every 5 days against Biological clock's every 13 months. Biological clock's advantage is iOS requirement (12.1 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Biological clock ships an update every 13 months, 鏡文字の逆読みONLINE every 5 days. The most recent releases landed on October 26, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Biological clock | 鏡文字の逆読みONLINE |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | Every 13 months | **Every 5 days** |
| Size | 13 MB | 68 MB |
| Requires iOS | **12.1** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [HAREPPO](https://appshunter.io/developer/604325074) | [BEAK,K.K.](https://appshunter.io/developer/1808079760) |

## What reviewers say

### Biological clock

[App page](https://appshunter.io/ios/app/biological-clock-everywhere/id1099546322)

**Features:** Vision Pro support

**In-app purchases:** none


### 鏡文字の逆読みONLINE

[App page](https://appshunter.io/ios/app/online/id6754183448)

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

**In-app purchases:** none


## Frequently asked questions

### Is Biological clock free?

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

### Is 鏡文字の逆読みONLINE free?

鏡文字の逆読みONLINE is free to download, with no in-app purchases.

### Do Biological clock or 鏡文字の逆読みONLINE have ads?

Both Biological clock and 鏡文字の逆読みONLINE show ads.

### Which is updated more often, Biological clock or 鏡文字の逆読みONLINE?

Biological clock ships an update every 13 months, and 鏡文字の逆読みONLINE every 5 days. Most recently, Biological clock was updated on October 26, 2026 and 鏡文字の逆読みONLINE 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.*