Comparison

Dive Toolbox vs Fathom Dive Planner

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Dive Toolbox

Features
Read full description

DiveToolbox — Professional dive planning and gas calculation tools for recreational and technical divers. DECOMPRESSION DIVE PLANNER Plan single-level and multi-level dives using the Bühlmann ZH-L16C algorithm with configurable gradient factors. Get detailed ascent profiles, gas switch schedules, and comprehensive safety analysis including CNS, OTU, gas density, and END monitoring. GAS BLENDING CALCULATOR Step-by-step fill instructions for Nitrox and Trimix blending. Supports partial pressure and continuous flow methods with real-time MOD calculations. MOD / EAD / END CALCULATOR Instantly calculate Maximum Operating Depth, Equivalent Air Depth, and Equivalent Narcotic Depth for any gas mix. GRADIENT FACTORS EXPLORER Visualize how GF Low and GF High affect no-decompression limits and decompression schedules. SAC RATE CALCULATOR Calculate your Surface Air Consumption rate from dive data to improve gas planning accuracy. ROCK BOTTOM CALCULATOR Determine minimum gas reserves for safe ascent, including emergency scenarios with configurable safety margins. SUCCESSIVE DIVE PLANNER Plan repetitive dives accounting for residual nitrogen and helium tissue loading from previous dives. UNIT CONVERSIONS Convert between metric and imperial units for depth, pressure, volume, and temperature. KEY FEATURES • Multi-gas support with automatic deco gas switching • Save and organize dive plans in folders • Save tank presets for quick planning • Share plans via link or QR code • Export plans as PDF • Customizable diver profile (GF, SAC, PPO2, speeds) • Dark and light themes • Available in 7 languages: English, French, German, Spanish, Italian, Polish, Russian Terms of Use: https://divetoolbox.com/en/terms Privacy Policy: https://divetoolbox.com/en/privacy

About

Fathom Dive Planner

Features
Read full description

Fathom is a native iPhone and iPad app for dive planning and logging. Build open- and closed-circuit decompression schedules with configurable gradient factors, then record every dive you make in the built-in logbook, and link each logged dive back to the plan that produced it. Build single- or multi-level dive plans, manage your gas mixes and tanks, and review every parameter that goes into your decompression schedule before you get in the water. After the dive, capture depth, time, gases, tanks, buddies, locations, and tags in a logbook designed for the same workflow. PLANNING • Configurable gradient factors (default GF 20/85) • Multi-level dive plans with automatic gas selection • Full trimix and heliox support, in addition to air and nitrox • Closed-circuit rebreather plans: fixed setpoints with a switch depth, and travel diluent for deep dives • Open-circuit bailout schedules computed from the worst point of the dive • Repetitive dives: tissue loading, CNS, and OTU carry across surface intervals • Custom gas mixes and standard preset catalogue • Tank and cylinder tracking with SAC and per-tank gas usage • Minimum gas (rock-bottom) reserve required to bring you and your buddy back from depth • NDL (no-decompression limit) at any depth • MOD, END, and gas density for every level, with warnings when a mix gets too dense • CNS clock and OTU oxygen exposure tracking LOGBOOK • Log every dive with depth, time, gases, tanks, location, buddies, and tags • Link each logged dive to its original plan • Browse and search your dive history GENERAL • Metric and imperial units throughout • iCloud sync across your iPhone, iPad, and Mac • One purchase unlocks Fathom on iPhone, iPad, and Mac IMPORTANT Fathom is a planning tool, not a substitute for diver training, qualified instruction, or the judgment of a certified dive professional. Always follow the procedures taught in your training agency, the limits of your certification, and your own dive computer. Decompression diving carries inherent risks. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Dive Toolbox4 screens
Fathom Dive Planner4 screens

Verdict

The call

The clearest difference is update cadence: Fathom Dive Planner at every 2 days against Dive Toolbox's every 6 days. Dive Toolbox's advantage is iOS requirement (15.0 vs 18.0). On price, 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Dive Toolbox sells 2 in-app purchases, starting at $5.99 per month and Fathom Dive Planner sells 2 in-app purchases, starting at $2.99 per year. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Dive Toolbox ships an update every 6 days, Fathom Dive Planner every 2 days. The most recent releases landed on November 9, 2026 and November 5, 2026 respectively.

Scorecard2 real differences · 4 level
Dive Toolbox versus Fathom Dive Planner: the parameters behind the verdict, then further details
ParameterDive ToolboxFathom Dive Planner
PriceFreeFree
Update frequencyEvery 6 daysEvery 2 days — better
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS15.0 — better18.0
Further details — not scored
Size33 MB8 MB
Age rating4+4+
DeveloperOnosiaTotal Immersion

In-app purchases

2 purchases

Dive Toolbox

Subscriptions1
  • Premium Monthly7 Days trial$5.991 Month
One-time1
  • Premium Lifetime$24.99
2 purchases

Fathom Dive Planner

Subscriptions1
  • Fathom Premium - Annual14 Days trial$2.991 Year
One-time1
  • Fathom Premium - Lifetime$14.99

Questions

Is Dive Toolbox free?
Dive Toolbox is free to download, with in-app purchases available.
Is Fathom Dive Planner free?
Fathom Dive Planner is free to download, with in-app purchases available.
Do Dive Toolbox or Fathom Dive Planner have ads?
Neither Dive Toolbox nor Fathom Dive Planner shows ads.
Which is updated more often, Dive Toolbox or Fathom Dive Planner?
Dive Toolbox ships an update every 6 days, and Fathom Dive Planner every 2 days. Most recently, Dive Toolbox was updated on November 9, 2026 and Fathom Dive Planner on November 5, 2026.

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