Introducing Dalton: Know Your Mix Before You Get Wet

Dalton is a technical diving gas calculator for iPhone and iPad. It does the gas math you already know how to do by hand – faster, with fewer mistakes, and with every formula sourced and verifiable. Available now on the App Store and Google Play.

Why we built it

If you plan your own dives, you run gas calculations. On paper, on a whiteboard, in a spreadsheet, or in your head at the fill station. The math is not complicated. But doing it repeatedly under time pressure is where errors happen – wrong decimal placement on an fO2 fraction, a forgotten unit conversion, a mental arithmetic slip on a ppO2 check.

Dalton does not replace your training or your judgment. It is a verification tool. You run your numbers, and Dalton confirms them. Or it catches the one you got wrong.

What it does

Dalton ships with seven tools organized into two sections.

Gas Calculations:

• Operating Limits – Calculate MOD and Minimum Operating Depth for any gas mix, including hypoxic trimix. Set your ppO2 ceiling between 1.2 and 1.6 bar.
• Equivalent Depths – EAD and END calculations side by side. See how your nitrox or trimix mix compares to air at the same depth.
• Gas Properties – Partial pressures (ppO2, ppN2, ppHe) and gas density at any depth. Gas density above 5.7 g/L gets flagged – a threshold supported by current research on work of breathing.
• Best Mix – Enter a target depth and ppO2 limit, get the optimal nitrox blend. No guesswork at the fill station.

These four tools are free on iOS – a complete gas calculator, no purchase required.

The three dive planning tools are available as a one-time Pro unlock.

Dive Planning:

• Return Number – Calculate how much gas you need to get back from a given depth, accounting for your SAC rate, ascent profile, and safety stop.
• Dive Profile Advisor – Build multi-segment depth profiles and see gas requirements, NDLs, and safety warnings at each level change. Not a decompression planner – a pre-dive sanity check for your gas supply.
• Bottom Time – How long can you stay at depth on a given tank? Enter your cylinder size, working pressure, SAC rate, and the math is done.

Every tool supports air, standard nitrox mixes (EAN32, EAN36), and custom trimix blends. Results include the source formula so you can verify the math yourself.

Verified against industry standards

Every calculation in Dalton has been cross-checked against published nitrox and trimix reference tables, dive computer firmware, and established gas physics formulas. The math is transparent, the sources are cited, and you can verify every result yourself – that’s the point.

We publish the formulas and their derivations inside the app. No black boxes. No proprietary algorithms.

How it works in practice

Dalton is designed to be used at the dive site, on the boat, or at the fill station. It works offline. There is no account to create, no data to sync, no subscription to manage. You buy it once and it is yours.

Results can be shared as cards – useful for sending your gas plan to a buddy or posting to a group chat before a dive.

Safety warnings use a three-tier system: informational notes, cautions for parameters approaching limits, and hard warnings when a value exceeds accepted thresholds. The warnings are based on published limits, not arbitrary choices.

Who it is for

Dalton is built for divers who plan their own dives. Technical divers running trimix. Cave divers calculating turn pressures. Nitrox divers checking their MOD before every fill. Instructors verifying student calculations. Anyone who wants a second opinion on their gas math before they get wet.

It is not a dive computer. It is not a decompression planner. It is a gas calculator that does its job and stays out of your way.

Availability

Dalton is available on the App Store and Google Play. The four gas calculation tools are free. The three dive planning tools unlock with a one-time Pro purchase. No ads, no subscriptions. Available in English, Spanish, and French.

Your gas plan is not someone else’s problem.