# Eナビストーマ vs 酸素ボンベの残量計算 / O2Calc

The clearest difference is device support: Eナビストーマ at 3 against 酸素ボンベの残量計算 / O2Calc's 1. Eナビストーマ also leads on iOS requirement (12.0 vs 18.0). On price, update cadence, ads and in-app purchases there is nothing between them.

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

Eナビストーマ ships an update every 2 months, 酸素ボンベの残量計算 / O2Calc every 6 weeks. The most recent releases landed on September 29, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Eナビストーマ | 酸素ボンベの残量計算 / O2Calc |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 6 weeks** |
| Monetization | — | Free with in-app purchases |
| Size | 41 MB | 8 MB |
| Requires iOS | **12.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 17+ | 17+ |
| Developer | [Koshiya medical care kk](https://appshunter.io/developer/543547305) | [Kazuhiro Higuchi](https://appshunter.io/developer/1887293944) |

## What reviewers say

### Eナビストーマ

[App page](https://appshunter.io/ios/app/e/id1498872869)

**Features:** macOS Compatibility

**In-app purchases:** none


### 酸素ボンベの残量計算 / O2Calc

[App page](https://appshunter.io/ios/app/o2calc/id6765861239)

This medical utility app assists healthcare professionals with critical oxygen management calculations. It offers features like oxygen remaining time estimation, FiO2 calculation, and pressure unit conversion, all within a clean, ad-free, and offline-capable interface.

**Highlights:** Oxygen remaining time calculation, FiO2 estimation by device, Pressure unit conversion, 3-stage abnormal value alerts, Double-check screen, Independent dark mode, Live Activities & Dynamic Island integration

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

**In-app purchases:** none


## Frequently asked questions

### Is Eナビストーマ free?

Eナビストーマ is free to download, with no in-app purchases.

### Is 酸素ボンベの残量計算 / O2Calc free?

酸素ボンベの残量計算 / O2Calc is free to download, with no in-app purchases.

### Do Eナビストーマ or 酸素ボンベの残量計算 / O2Calc have ads?

Neither Eナビストーマ nor 酸素ボンベの残量計算 / O2Calc shows ads.

### Which is updated more often, Eナビストーマ or 酸素ボンベの残量計算 / O2Calc?

Eナビストーマ ships an update every 2 months, and 酸素ボンベの残量計算 / O2Calc every 6 weeks. Most recently, Eナビストーマ was updated on September 29, 2026 and 酸素ボンベの残量計算 / O2Calc on October 8, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*