Nitrox Buddy vs SDI TDI ERDI PFI
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.
SDI TDI ERDI PFI
This app serves as a comprehensive diving companion, allowing users to log dives, manage digital certifications, update personal profiles, and find dive centers and instructors globally. It also provides access to exclusive content from multiple diving agencies.
- Dive log with offline support
- Digital certification access and sharing
- Personalized profile management
- Global dive center and instructor search
- Access to diving blogs and videos
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SDI/TDI/ERDI/PFI Mobile App – Your Ultimate Diving Companion Discover the NEW all-in-one diving app from YOUR ONE DIVE FAMILY at Scuba Diving International (SDI), Technical Diving International (TDI), Emergency Response Diving International (ERDI), and Performance Freediving International (PFI). Whether you're logging dives, managing certifications, or exploring new dive sites, the SDI/TDI/ERDI/PFI Mobile App is designed to enhance your diving experience. NEW! Dive Log Feature Track your dives effortlessly with our new Dive Log! Log completed dives, manage training sessions with your instructor, and keep all your dive records in one place. With offline support, you can even save and access logs without an internet connection. Plus, upload up to five images to capture each dive's highlights. Digital Certifications – Always with You Never worry about carrying physical certification cards again! Instantly access, download, and share your SDI, TDI, ERDI, and PFI certifications directly from the app. No syncing or extra payment required—just log in, and your digital certs are ready to go. Personalized Profile Management Easily update your profile, contact information, and photo directly through the app. Stay up to date with your diving credentials anytime, anywhere. Find Dive Centers & Instructors Worldwide Looking for your next adventure? Search for SDI/TDI/ERDI/PFI-affiliated dive centers and instructors no matter where you are in the world. Explore SDI/TDI/ERDI/PFI Content Stay connected with the latest diving insights. Access blogs, videos, and expert content from across all our agencies in one place.
Screenshots
Verdict
The clearest difference is review sentiment: Nitrox Buddy at 96% against SDI TDI ERDI PFI's 40%. Nitrox Buddy also leads on rating (4.9 vs 4.3) and ratings volume (468 vs 150). SDI TDI ERDI PFI's advantage is in-app purchases (none vs 1) and update cadence (every 2 months vs every 7 months). 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. SDI TDI ERDI PFI asks for nothing beyond the download.
Nitrox Buddy holds the better App Store score, 4.9 against 4.3. Both are backed by a comparable volume of ratings — 468 and 150 respectively. Written reviews point the same way: 96% of Nitrox Buddy's written reviews are positive against 40% of SDI TDI ERDI PFI's.
Nitrox Buddy ships an update every 7 months, SDI TDI ERDI PFI every 2 months. The most recent releases landed on September 21, 2026 and September 24, 2026 respectively.
| Parameter | Nitrox Buddy | SDI TDI ERDI PFI |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (468 ratings) — better | 4.3 (150 ratings) |
| Positive reviews | 95.7% of reviews — better | 40.0% of reviews |
| Number of ratings | 468 — better | 150 |
| 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, iPod |
| Requires iOS | 26.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 6 MB | 58 MB |
| Age rating | 4+ | 4+ |
| Developer | Gereon Steffens | ITI Holdings, LLC. |
Customer experience
Nitrox Buddy
SDI TDI ERDI PFI
User reviews
Nitrox Buddy
From 468 App Store ratingsWhat we love
- 👍 Easy to use
- 🚀 Quick calculations
- ✅ Accurate results
- 💡 Free to use
- 🎯 Essential for Nitrox divers
Room to improve
- 📱 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
SDI TDI ERDI PFI
From 150 App Store ratingsWhat we love
- 👍 Access to eCards
- 👍 Great resource for professionals
- 👍 Good for documenting dive information
- 👍 Informative publications
- 👍 User-friendly certification agency app
Room to improve
- 🐛 Crashing after update
- 🐛 Very glitchy
- 🐛 Laggy, especially selecting dive sites
- 🐛 Buttons unintuitive
- 🐛 Slow manual dive loading
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)
SDI TDI ERDI PFI
Reported bugs
10 issues- Cannot log out
- Dive logs not found after download
- App crashing after update
- Very glitchy
- Laggy, especially when selecting dive sites
Show 5 moreShow fewer
- Constant sign outs
- Losing session, requires login each time
- Mandatory update popup without 'later' option
- Basic and buggy
- Session expired every time
Requested features
17 requests- iPad OS integration
- Import dive logs via spreadsheet/Google Sheets
- See dive notes in log details
- Autofill for consecutive dives/same site
- Input courses and buddies not in SDI database
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- Option to edit dives (add companions)
- iPad optimized design
- Diver tables for planning
- Online learning through the app
- Logbook feature
- Dashboard with progress and certifications
- Apple Wallet integration
- Store certification card in Apple Wallet
- Dive log integration
- Dive tools
- Course learning integrated into app
- Mobile app support for eLearning sign-up/class access
In-app purchases
Nitrox Buddy
- Tip$0.99
SDI TDI ERDI PFI
No in-app purchases
Questions
Is Nitrox Buddy free?
Is SDI TDI ERDI PFI free?
Which has better reviews, Nitrox Buddy or SDI TDI ERDI PFI?
Do Nitrox Buddy or SDI TDI ERDI PFI have ads?
Which is updated more often, Nitrox Buddy or SDI TDI ERDI PFI?
Other comparisons
