# 酸素ボンベの残量計算 / O2Calc vs Drip Rate Calculator

The clearest difference is in-app purchases: 酸素ボンベの残量計算 / O2Calc at none against Drip Rate Calculator's 1. Drip Rate Calculator's advantage is update cadence (every 9 days vs every 6 weeks) and device support (3 vs 1). On price, ads, monetization model and iOS requirement there is nothing between them.

Both are free to download. Drip Rate Calculator sells 1 one-off in-app purchase. 酸素ボンベの残量計算 / O2Calc asks for nothing beyond the download.

酸素ボンベの残量計算 / O2Calc ships an update every 6 weeks, Drip Rate Calculator every 9 days. The most recent releases landed on October 8, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | 酸素ボンベの残量計算 / O2Calc | Drip Rate Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (1 ratings)](https://appshunter.io/ios/app/drip-rate-calculator/id6775409848/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Every 9 days** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 8 MB | 23 MB |
| Requires iOS | 18.0 | 18.0 |
| Devices | iPhone | **iPhone, iPad, Apple Watch** |
| Age rating | 17+ | 4+ |
| Developer | [Kazuhiro Higuchi](https://appshunter.io/developer/1887293944) | [Romiick LLC](https://appshunter.io/developer/1716146475) |

## What reviewers say

### 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


### Drip Rate Calculator

[App page](https://appshunter.io/ios/app/drip-rate-calculator/id6775409848)

This medical app assists nurses and healthcare professionals in calculating IV drip rates. It provides estimated drip counts, intervals, and flow rates, with companion Apple Watch functionality for convenient wrist-based adjustments and rhythm checks. A free version offers core features, with a one-time purchase for Pro to unlock advanced options.

**Highlights:** Calculate drops per minute, Calculate seconds per drop, Show hourly infusion volume, Support adult and pediatric IV sets, Apple Watch integration for results and adjustments, Rhythm check with sound or vibration, Multiple timers with notifications

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Version | $9.99 | one-time |


## Frequently asked questions

### 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.

### Is Drip Rate Calculator free?

Drip Rate Calculator is free to download, with in-app purchases available.

### Do 酸素ボンベの残量計算 / O2Calc or Drip Rate Calculator have ads?

Neither 酸素ボンベの残量計算 / O2Calc nor Drip Rate Calculator shows ads.

### Which is updated more often, 酸素ボンベの残量計算 / O2Calc or Drip Rate Calculator?

酸素ボンベの残量計算 / O2Calc ships an update every 6 weeks, and Drip Rate Calculator every 9 days. Most recently, 酸素ボンベの残量計算 / O2Calc was updated on October 8, 2026 and Drip Rate Calculator 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.*