CCR MOD

CCR trimix MOD calculator with blending guide and pre-dive checklist. Works offline. No account required.

CR MOD is a dive planning tool for closed-circuit rebreather divers using trimix or nitrox fills. It runs entirely on your device — no internet connection required.

MOD Calculator Enter your oxygen and helium percentages and your target PPO₂ to instantly see the maximum operating depth for your gas mix. The calculator evaluates all three limiting factors simultaneously — PPO₂, gas density, and equivalent narcotic depth (END) — and tells you which one is constraining your dive.

Trimix Blending Calculator Calculate the exact steps needed to blend a trimix fill from your current tank contents. Enter the current mix and pressure, enter your target mix and pressure, and receive a step-by-step blending sequence: bleed, add helium, add oxygen, top with air.

Pre-dive Checklist A CCR pre-dive checklist covering cell dates, scrubber time, cylinder pressures, O-rings, loop integrity, negative and positive pressure tests, MAVs, ADV, and more. Checklist state is saved between sessions.

Settings Switch between metric and imperial display units. Configure the maximum gas density limit, maximum END, and gas component densities.

Safety notice: While reasonable care has been taken to ensure accuracy, independent verification of all results is strongly recommended. Using this application without appropriate CCR training and without verifying results may result in serious injury or death.