Nitrox Buddy vs Subsurface
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Nitrox Buddy
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.
- 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
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Nitrox Buddy is a no-frills calculator app for nitrox/enriched air divers - use it to quickly calculate the most important data for your dive: Maximum Operating Depth/MOD, Equivalent Air Depth/EAD, Best Mix and PPO2. The app works with imperial or metric measurements, sea or fresh water, and allows you to select the maximum oxygen content and partial pressure. A companion watch app puts lets you perform all these calculations on your wrist.
Subsurface
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.
- Mobile dive log management
- Edit dive data
- Download from Bluetooth LE dive computers
- Optional cloud synchronization
- Open-source and free
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Subsurface-mobile is an iOS dive log application based on Subsurface, the best free open source dive log application available on Windows, Mac and Linux. Subsurface-mobile allows you to access your dive log on your tablet or phone, edit the data and even download new dive information from many Bluetooth LE enabled dive computers. Using a free Subsurface Cloud Storage account you can synchronize your dive data with the Subsurface desktop application (while significantly increasing the usefulness, the cloud account is not required to use Subsurface-mobile). To get support from the developers, please use the in-app menu entry "Ask for support" Please check out the Subsurface-mobile user manual: https://subsurface-divelog.org/documentation/subsurface-mobile-v3-user-manual (also available from within the app) Subsurface-mobile is free and open source. No ads, no commercial anything. And it comes with free cloud storage (if you decide to use that - it's optional). Your data aren't used for anything, nothing gets monetized.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | Nitrox Buddy | Subsurface |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (468 ratings) — better | 4.5 (48 ratings) |
| Positive reviews | 95.7% of reviews — better | 63.3% of reviews |
| Number of ratings | 468 — better | 48 |
| Update frequency | Every 7 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPod, Apple Watch — better | iPhone, iPad |
| Requires iOS | 26.0 | 17 — better |
| Further details — not scored | ||
| Size | 6 MB | 52 MB |
| Age rating | 4+ | 4+ |
| Developer | Gereon Steffens | Dirk Hohndel |
Customer experience
Nitrox Buddy
Subsurface
Bugs and requests
Nitrox Buddy
Reported bugs
4 issues- 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
4 requests- 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
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Nitrox Buddy
- Tip$0.99
Subsurface
No in-app purchases
Questions
Is Nitrox Buddy free?
Is Subsurface free?
Which has better reviews, Nitrox Buddy or Subsurface?
Do Nitrox Buddy or Subsurface have ads?
Which is updated more often, Nitrox Buddy or Subsurface?
Other comparisons
