# Chrono Rainbow vs zen

The clearest difference is price: Chrono Rainbow at Free against zen's $0.99. Chrono Rainbow also leads on iOS requirement (18.5 vs 26.0). zen's advantage is in-app purchases (none vs 2) and update cadence (every 5 days vs every 2 weeks). On review sentiment, ads and device support there is nothing between them.

Chrono Rainbow is free to download; zen costs $0.99 up front. Chrono Rainbow sells 2 in-app purchases, starting at $0.29 per month. zen asks for nothing beyond the download.

Chrono Rainbow ships an update every 2 weeks, zen every 5 days. The most recent releases landed on October 8, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | Chrono Rainbow | zen |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Every 5 days** |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 86 MB | 6 MB |
| Requires iOS | **18.5** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 12+ |
| Developer | [Toshiaki Nakamura](https://appshunter.io/developer/822485897) | [Taiyo Fujii](https://appshunter.io/developer/1889371389) |

## What reviewers say

### Chrono Rainbow

[App page](https://appshunter.io/ios/app/chrono-rainbow/id6739449092)

This app visualizes your time with both Western and Japanese calendars, allowing you to register special dates and track yearly progress. It offers customizable themes and integrates traditional Japanese seasonal markers.

**Highlights:** Western and Japanese calendar display, Anniversary and birthday registration, Japanese seasonal markers, Yearly progress visualization, Customizable themes, Traditional Japanese colors

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Chrono Colors Plan 1 month | $0.29 | per month |
| Chrono Colors Plan 1 year | $2.99 | per year |


### zen

[App page](https://appshunter.io/ios/app/zen-babel/id6761398433)

Translate text and documents offline using your device. This app prioritizes privacy by keeping all data local, offering both fast machine translation and AI-powered options. It supports various file formats and image text extraction.

**Highlights:** Offline translation, On-device processing, Text and image translation, Supports various file types, Machine and AI translation options, Side-by-side comparison

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

**In-app purchases:** none


## Frequently asked questions

### Is Chrono Rainbow free?

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

### Is zen free?

zen costs $0.99, with no in-app purchases.

### Do Chrono Rainbow or zen have ads?

Neither Chrono Rainbow nor zen shows ads.

### Which is updated more often, Chrono Rainbow or zen?

Chrono Rainbow ships an update every 2 weeks, and zen every 5 days. Most recently, Chrono Rainbow was updated on October 8, 2026 and zen on October 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.*