# BIO3 vs CircadiaOS

The clearest difference is rating: BIO3 at 5.0 against CircadiaOS's 3.8. BIO3 also leads on in-app purchases (none vs 4) and ads (none vs shown). CircadiaOS's advantage is ratings volume (10 vs 2). On price, update cadence, device support and iOS requirement there is nothing between them.

Both are free to download. CircadiaOS sells 4 in-app purchases, starting at $9.99 per month. BIO3 asks for nothing beyond the download.

BIO3 holds the better App Store score, 5.0 against 3.8. That said, the two scores are not equally well evidenced: CircadiaOS has 10 ratings behind it against 2, so its average is the more settled of the two.

BIO3 ships an update every 2 days, CircadiaOS every 3 days. The most recent releases landed on October 16, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | BIO3 | CircadiaOS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/bio3/id6761016490/reviews)** | [3.8 (10 ratings)](https://appshunter.io/ios/app/circadiaos-sleep-tracker/id6761959749/reviews) |
| Number of ratings | 2 | **10** |
| Positive reviews | — | 75.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 2 days** | Every 3 days |
| Monetization | **Free** | Free with in-app purchases |
| Size | 4 MB | 25 MB |
| Requires iOS | 18.5 | **18.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [Yashaswini Rajendra Bhat](https://appshunter.io/developer/1887321102) | [CircadiaOS LLC](https://appshunter.io/developer/1892208236) |

## What reviewers say

### BIO3

[App page](https://appshunter.io/ios/app/bio3/id6761016490)

This app helps Dartmouth College BIO3 students track their mindfulness practice. Log meditation sessions, monitor progress, and view course leaderboard standings. It prioritizes user privacy with secure data storage and opt-in research participation.

**Highlights:** Log meditation sessions (duration, quality, stress), Track group practice participation, Monitor personal progress, View course leaderboard, Access mindfulness resources, Secure data storage

**Features:** macOS Compatibility

**In-app purchases:** none


### CircadiaOS

[App page](https://appshunter.io/ios/app/circadiaos-sleep-tracker/id6761959749)

This app learns your body's ideal sleep temperature and automatically adjusts your smart thermostat throughout the night. It uses data from your wearable to personalize a four-phase temperature schedule for optimal sleep recovery. Requires a compatible smart thermostat and sleep-tracking wearable.

**Highlights:** Learns ideal sleep temperature, Personalized four-phase temperature schedule, Integrates with smart thermostats, Syncs with sleep-tracking wearables, Analyzes sleep quality, Two-week calibration period

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CircadiaOS Lite Monthly | $9.99 | per month |
| CircadiaOS | $19.99 | per month |
| CircadiaOS Lite Yearly | $99.99 | per year |
| CircadiaOS | $159.99 | per year |


## Frequently asked questions

### Is BIO3 free?

BIO3 is free to download, with no in-app purchases.

### Is CircadiaOS free?

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

### Which has better reviews, BIO3 or CircadiaOS?

BIO3 is rated higher. BIO3 averages 5.0 out of 5 from 2 ratings, while CircadiaOS averages 3.8 from 10 ratings.

### Do BIO3 or CircadiaOS have ads?

CircadiaOS shows ads; BIO3 does not.

### Which is updated more often, BIO3 or CircadiaOS?

BIO3 ships an update every 2 days, and CircadiaOS every 3 days. Most recently, BIO3 was updated on October 16, 2026 and CircadiaOS 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.*