# Nitrox Buddy vs Subsurface

The clearest difference is in-app purchases: Subsurface at none against Nitrox Buddy's 1. Subsurface also leads on update cadence (every 2 months vs every 7 months) and iOS requirement (17 vs 26.0). Nitrox Buddy's advantage is review sentiment (96% vs 63%) and rating (4.9 vs 4.5). On price, ads and device support there is nothing between them.

Both are free to download. Nitrox Buddy sells 1 one-off in-app purchase. Subsurface asks for nothing beyond the download.

Nitrox Buddy holds the better App Store score, 4.9 against 4.5. That said, the two scores are not equally well evidenced: Nitrox Buddy has 468 ratings behind it against 48, so its average is the more settled of the two. Written reviews point the same way: 96% of Nitrox Buddy's written reviews are positive against 63% of Subsurface's.

Nitrox Buddy ships an update every 7 months, Subsurface every 2 months. The most recent releases landed on September 21, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | Nitrox Buddy | Subsurface |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (468 ratings)](https://appshunter.io/ios/app/nitrox-buddy/id572411073/reviews)** | [4.5 (48 ratings)](https://appshunter.io/ios/app/subsurface-mobile/id1093217161/reviews) |
| Number of ratings | **468** | 48 |
| Positive reviews | **95.7% of reviews** | 63.3% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 7 months | **Every 2 months** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 6 MB | 52 MB |
| Requires iOS | 26.0 | **17** |
| Devices | **iPhone, iPod, Apple Watch** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Gereon Steffens](https://appshunter.io/developer/493030228) | [Dirk Hohndel](https://appshunter.io/developer/1093217160) |

## What reviewers say

### Nitrox Buddy

[App page](https://appshunter.io/ios/app/nitrox-buddy/id572411073)

This application serves as a straightforward calculator for nitrox and enriched air divers. It quickly computes essential dive data such as Maximum Operating Depth (MOD), Equivalent Air Depth (EAD), Best Mix, and Partial Pressure of Oxygen (PPO2). It supports both imperial and metric units and offers a companion watch app for on-the-go calculations.

**Highlights:** Calculate MOD, EAD, Best Mix, PPO2, Imperial and metric unit support, Sea and fresh water options, Selectable max oxygen content, Selectable max partial pressure, Companion watch app

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Tip | $0.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 🚀 Quick calculations
- ✅ Accurate results
- 💡 Free to use
- 🎯 Essential for Nitrox divers

**What reviewers complain about**

- 📱 Ugly iPad icon
- ⚠️ MOD calculation limited to 40% O2 in older versions
- ⚠️ MOD calculation limited to 50% O2 in older versions
- ⚠️ Needs to work with older iOS versions

**Reported bugs**

- iPad icon is ugly
- MOD limit of 50% O2 despite 100% O2 setting (resolved)
- MOD limit of 40% O2 (older version)
- Does not work with older iOS versions

**Requested features**

- Add MOD 1.5 option
- Allow MOD calculation up to 100% O2 and indicate max exposure duration
- Change color for inappropriate mixes (e.g., 50% at 40m)
- Support older iOS versions (5 & 6)


### Subsurface

[App page](https://appshunter.io/ios/app/subsurface-mobile/id1093217161)

This application allows divers to manage their dive logs on their mobile devices. It supports editing dive data and downloading new information from compatible dive computers. Optional cloud synchronization is available for seamless data transfer with desktop versions.

**Highlights:** Mobile dive log management, Edit dive data, Download from Bluetooth LE dive computers, Optional cloud synchronization, Open-source and free

**In-app purchases:** none


## Frequently asked questions

### Is Nitrox Buddy free?

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

### Is Subsurface free?

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

### Which has better reviews, Nitrox Buddy or Subsurface?

Nitrox Buddy is rated higher. Nitrox Buddy averages 4.9 out of 5 from 468 ratings, while Subsurface averages 4.5 from 48 ratings.

### Do Nitrox Buddy or Subsurface have ads?

Neither Nitrox Buddy nor Subsurface shows ads.

### Which is updated more often, Nitrox Buddy or Subsurface?

Nitrox Buddy ships an update every 7 months, and Subsurface every 2 months. Most recently, Nitrox Buddy was updated on September 21, 2026 and Subsurface on September 18, 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.*