Calculating MOD, PO₂ and EAD When Diving Nitrox

This calculator shows how depth, gas mix, and oxygen exposure relate when diving with Nitrox. It calculates the maximum operating depth (MOD) for a given FO₂ and PO₂ limit, and highlights when oxygen exposure exceeds safe levels. For a detailed explanation of how MOD is calculated using Dalton's Triangle and why PO₂ limits matter, see the Maximum Operating Depth Deep Dive.

The table also includes Equivalent Air Depth (EAD) to help visualize how Nitrox affects potential nitrogen narcosis. Even though Nitrox reduces nitrogen loading, dives can still be narcotic at depth — especially below 100 feet.


PO₂ > 1.4 ATA
PO₂ > 1.6 ATA
Depth (ft) FO₂ (%) PO₂ (ATA) EAD (ft)