Nitrox Buddy vs Thalos
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.
Thalos
This comprehensive dive app offers a robust dive logbook, detailed dive site information with emergency plans, and multiple dive calculators. It includes features for instructors to manage students and courses, and a social feed for divers to connect and share experiences. The app works fully offline, ensuring critical data is always accessible.
- Offline dive logbook
- Dive site database with emergency plans
- 9 essential dive calculators
- Instructor module for course management
- Social feed and community features
- Emergency mode for critical access
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Thalos is the all-in-one dive app built for serious divers and instructors. Whether you're planning a deep technical dive or running an open water course, Thalos has everything you need — and it works fully offline when it matters most. DIVE LOGBOOK Log every dive with depth, time, gas, conditions, marine life sightings, buddy signatures, and photos. Full version history keeps your records safe. Organize dives into trips and track your personal certifications. DIVE SITES & EMERGENCY PLANS Access 510+ dive sites with detailed emergency action plans, nearest hyperbaric chambers, and emergency contacts — all stored locally so they're available even without signal. 9 DIVE CALCULATORS • Bühlmann ZHL-16C decompression planner with gradient factors • Gas planner and gas blending • SAC rate, turn pressure, weight calculator • Dive tables, unit converter, altitude diving EMERGENCY MODE One tap gets you to emergency procedures and critical contacts. Works 100% offline. INSTRUCTOR MODULE Manage students, run courses with 26 built-in templates, track skill sign-offs, generate paperwork (liability waivers, medical forms, training dives), and issue certifications. SOCIAL FEED & TANK TAPS Share your dives, follow other divers, and give Tank Taps — the diver's way of saying nice dive. COMMUNITY Discover and post dive classes, trips, and dive centers. Instructors can manage enrollments directly in the app. SUBSCRIPTION Thalos requires a subscription after a 1-month free trial. $2.99/month or $19.99/year. Terms of Use: https://blackflagdivecenter.github.io/Thalos/terms.html Privacy Policy: https://blackflagdivecenter.github.io/Thalos/privacy.html
Screenshots
Verdict
The clearest difference is monetization model: Nitrox Buddy at free with in-app purchases against Thalos's subscription. Nitrox Buddy also leads on ratings volume (468 vs 2). Thalos's advantage is update cadence (daily vs every 7 months) and iOS requirement (15.1 vs 26.0). On price, rating, ads and in-app purchases 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 and Thalos sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 4.9 for Nitrox Buddy against 5.0 for Thalos. That said, the two scores are not equally well evidenced: Nitrox Buddy has 468 ratings behind it against 2, so its average is the more settled of the two.
Nitrox Buddy ships an update every 7 months, Thalos daily. The most recent releases landed on October 14, 2026 and October 13, 2026 respectively.
| Parameter | Nitrox Buddy | Thalos |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (468 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 95.7% of reviews | — |
| Number of ratings | 468 — better | 2 |
| Update frequency | Every 7 months | Daily — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases — better | Subscription |
| Devices | iPhone, iPod, Apple Watch — better | iPhone, iPod |
| Requires iOS | 26.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 6 MB | 41 MB |
| Age rating | 4+ | 4+ |
| Developer | Gereon Steffens | JOHN WALLIS YOUNGBLOOD |
Customer experience
Nitrox Buddy
Thalos
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)
Thalos
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Nitrox Buddy
- Tip$0.99
Thalos
- Thalos1 Month trial$2.991 Month
- Thalos1 Month trial$19.991 Year
