# I/O Frog vs ChartDay

The clearest difference is in-app purchases: I/O Frog at none against ChartDay's 1. ChartDay's advantage is update cadence (every 3 weeks vs every 2 months) and iOS requirement (16.2 vs 18.0). On price, ads and device support there is nothing between them.

Both are free to download. ChartDay sells 1 one-off in-app purchase. I/O Frog asks for nothing beyond the download.

I/O Frog ships an update every 2 months, ChartDay every 3 weeks. The most recent releases landed on September 15, 2026 and June 1, 2026 respectively.

## The numbers

| Metric | I/O Frog | ChartDay |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (3 ratings)](https://appshunter.io/ios/app/chartday/id6446491718/reviews)** |
| Number of ratings | — | **3** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | — | Freemium |
| Size | 126 MB | 2 MB |
| Requires iOS | 18.0 | **16.2** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Sigfrog s.r.o.](https://appshunter.io/developer/531682348) | [Fu Ni](https://appshunter.io/developer/1560534229) |

## What reviewers say

### I/O Frog

[App page](https://appshunter.io/ios/app/io-frog/id1473247008)

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

**In-app purchases:** none


### ChartDay

[App page](https://appshunter.io/ios/app/chartday/id6446491718)

Track daily habits, health, and fitness with interactive charts. Offers instant statistics, goal setting, and data export. Syncs across devices and provides home screen widgets for quick access.

**Highlights:** Daily tracking with interactive charts, Instant statistical calculations, Goal setting with target lines, Tagging and filtering for organization, Home screen widgets, iCloud sync across devices, Data export to CSV

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ChartDay Unlimited | $1.99 | one-time |


## Frequently asked questions

### Is I/O Frog free?

I/O Frog is free to download, with no in-app purchases.

### Is ChartDay free?

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

### Do I/O Frog or ChartDay have ads?

Neither I/O Frog nor ChartDay shows ads.

### Which is updated more often, I/O Frog or ChartDay?

I/O Frog ships an update every 2 months, and ChartDay every 3 weeks. Most recently, I/O Frog was updated on September 15, 2026 and ChartDay on June 1, 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.*