# Oxyg'App vs Physics Constants Library

The clearest difference is in-app purchases: Oxyg'App at none against Physics Constants Library's 1. Oxyg'App also leads on ads (none vs shown) and update cadence (every 6 days vs every 7 months). On price and device support there is nothing between them.

Both are free to download. Physics Constants Library sells 1 one-off in-app purchase. Oxyg'App asks for nothing beyond the download.

Oxyg'App ships an update every 6 days, Physics Constants Library every 7 months. The most recent releases landed on September 12, 2026 and September 20, 2026 respectively.

## The numbers

| Metric | Oxyg'App | Physics Constants Library |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 6 days** | Every 7 months |
| Size | 32 MB | 10 MB |
| Requires iOS | **13.0** | 18.4 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [L'Institut universitaire de cardiologie et de pneumologie de Québec (IUCPQ)](https://appshunter.io/developer/576953454) | [ChatStick Company Limited](https://appshunter.io/developer/1165816085) |

## What reviewers say

### Oxyg'App

[App page](https://appshunter.io/ios/app/oxygapp/id1668892646)

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

**In-app purchases:** none


### Physics Constants Library

[App page](https://appshunter.io/ios/app/physics-constants-library/id6751224343)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Features | $2.99 | one-time |


## Frequently asked questions

### Is Oxyg'App free?

Oxyg'App is free to download, with no in-app purchases.

### Is Physics Constants Library free?

Physics Constants Library is free to download, with in-app purchases available.

### Do Oxyg'App or Physics Constants Library have ads?

Physics Constants Library shows ads; Oxyg'App does not.

### Which is updated more often, Oxyg'App or Physics Constants Library?

Oxyg'App ships an update every 6 days, and Physics Constants Library every 7 months. Most recently, Oxyg'App was updated on September 12, 2026 and Physics Constants Library on September 20, 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.*