CCR Mixer: Dive Gas Planner

CCR Mixer is a dive gas planner for closed-circuit rebreather and open-circuit mixed-gas diving. It covers the calculations a technical diver runs before a dive: the optimal loop mix for a target depth and ppO2 setpoint, blending plans for nitrox, trimix, and heliair, depth limits, and oxygen exposure. Everything runs on the device, offline, with no ads and no account.

This app is a planning aid for trained, certified mixed-gas divers. It does not replace training, supervision, or your own judgement, and every result must be verified with a calibrated analyser before the gas is breathed. A full disclaimer must be read and accepted before first use.

Planning Modes

• Optimal CCR Mix: the best diluent or loop mix for a planned depth against your ppO2 settings
• Nitrox blending: partial-pressure fill plans from your current cylinder contents
• Trimix blending: oxygen, helium, and top-up fill steps in order, with cumulative gauge pressures
• HeliAir blending: helium plus air fills
• Top up: what a given top-up gas does to the mix already in the cylinder
• What if: the resulting mix from any sequence of fills
• MOD, END, EAD, and EADD: depth limits for any mix against your maximum ppO2
• CNS and OTU: oxygen toxicity exposure for a planned dive

Blending That Fits Your Cylinder

Real cylinders are rarely empty. CCR Mixer plans from the gas you actually have, and when a target mix cannot be reached from the current contents, it calculates a drain-and-refill plan: bleed the cylinder down to a stated pressure, then add oxygen, helium, and top-up gas in the listed order. Where the target involves high-pressure helium, the app flags a compressibility advisory, because ideal-gas planning can under-deliver helium by a few percent in those blends.

Settings and Saved Mixes

• Salt or fresh water, which changes the pressure model
• Metric or imperial units (metres and bar, or feet and psi)
• Default ppO2 setpoint and maximum ppO2
• Saved mixes: name and store gas mixes, see each one's MOD at a glance

Accuracy and Limits

Be clear about what this dive gas planner is and is not. Blending uses the ideal-gas model that diver-facing calculators generally use, so real gas can differ, and the app says so where it matters. There is no decompression model: it does not replace a dive computer or deco software. It is not a medical device and not certified dive-planning software, and no agency has reviewed or approved it. Every value is an estimate. Analyse the finished mix with a calibrated oxygen analyser, and a helium analyser for trimix, before you dive it.

The calculation core is kept separate from the interface and is covered by a suite of golden-value tests checked by hand against textbook formulas.

Offline and Private

• Works fully offline: the app makes no network requests
• No ads, no account, no tracking
• Your settings and saved mixes stay on the device

Who It Is For

• CCR divers planning loop and diluent mixes
• Open-circuit technical divers blending nitrox or trimix
• Gas blenders who want fill steps from real cylinder contents rather than an empty-cylinder assumption

Gas-mixing and dive-planning mistakes can cause serious injury or death. Use this app only if you are trained and certified for the diving it describes, and always verify your gas before you breathe it.