Dive Gas Calculators: RMV, MOD, and Reserve Gas

If you know the theory behind gas planning but want help doing the math, this is where you start.

These calculators are designed for recreational divers and help answer practical questions like:

You don’t need to be an engineer. You just need to plug in the right numbers and understand what they mean.

Available Tools

RMV / SAC Calculator

This calculator helps you find your RMV and SAC rates based on dive data. RMV is the go-to number for gas planning because it's tank-independent and lets you estimate gas needs across different depths, dives, and setups.

MOD Calculator

This calculator helps you find the maximum operating depth (MOD) for your Nitrox mix based on oxygen limits. It also shows PO₂ exposure and equivalent air depth (EAD) to support safer gas planning and prevent oxygen toxicity.

Minimum Reserve Gas Calculator

This calculator estimates how much gas you need to ascend safely with a buddy in an emergency. Using the CAT method, it accounts for RMV, depth, time, and tank size to give you both volume and PSI values—plus a 500 PSI minimum for safety.