MultiDeco vs MyFathom
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MultiDeco
This app calculates dive decompression for technical scuba divers using VPM and ZHL-16 models. It supports various gas mixes, planning methods for open circuit and rebreathers, and includes tools for gas blending and depth calculations.
- VPM and ZHL-16 decompression models
- Support for nitrox and trimix
- OC and CCR planning
- Bailout planning
- Gas blending utility
- Depth calculation tools
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A dive decompression calculator for technical scuba divers. MultiDeco presents the VPM and ZHL-16 decompression model and includes VPM-B, VPM-B/E, ZHL model versions and ZHL-16 + GF. The diver can specify any combination of nitrox or trimix, and as many deco gases as required. Planning methods include both OC and Closed Circuit Rebreather. It includes planning for bailouts with SCR and OC legs in a CCR plan. Includes details of ppO2, END, and gas consumptions. This program includes many of the features from the desktop version such as conservatism adjustments, extended stops, adjustable last stops, the planning monitor system and extensive control over many other planning features. Also included is a set of dive planning tools for calculating best mix, maximum operating depth (MOD), END, EAD and other planning considerations. The Mixer utility for blending nitrox and trimix, is included too.
MyFathom
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The MyFathom app is the companion app for Fathom CCR divers with everything you need to support your rebreather diving. Features: - Build checklist - O2 cell performance monitoring - Dive log - Certification cards
Screenshots
Verdict
The clearest difference is price: MyFathom at Free against MultiDeco's $48.99. MyFathom also leads on iOS requirement (11.0 vs 17.6). MultiDeco's advantage is update cadence (every 3 months vs every 13 months). On ads, in-app purchases 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
MyFathom is free to download; MultiDeco costs $48.99 up front. Neither carries in-app purchases, so what you see is what you pay.
MultiDeco ships an update every 3 months, MyFathom every 13 months. The most recent releases landed on September 19, 2026 and September 9, 2026 respectively.
| Parameter | MultiDeco | MyFathom |
|---|---|---|
| Price | $48.99 | Free — better |
| Rating | 3.9 (11 ratings) — better | — |
| Positive reviews | 38.9% of reviews | — |
| Number of ratings | 11 — better | — |
| Update frequency | Every 3 months — better | Every 13 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.6 | 11.0 — better |
| Further details — not scored | ||
| Size | 2 MB | 35 MB |
| Age rating | 4+ | 4+ |
| Developer | HHS Software Corp. | FATHOM Dive Systems, LLC |
In-app purchases
MultiDeco
No in-app purchases
MyFathom
No in-app purchases
