Nitrox, Trimix & Gas Density Calculator for Scuba Divers

Nitrox, Trimix, MOD, Gas Density & EAD Calculator for Scuba Divers | Simple Dive Australia

This calculator suite is designed for recreational and technical divers in Australia, including students completing SDI Open Water, TDI Advanced Nitrox, Decompression Procedures, Trimix and Helitrox courses.

Maximum Operating Depth (MOD)
Optimal oxygen fraction for a target depth
Gas density including helium (He), oxygen (O₂), nitrogen (N₂)
Equivalent Air Depth (EAD / END) using two narcotic models
Surface Air Consumption (SAC)

Built by Simple Dive in Blackburn South, Melbourne, this tool follows industry-standard physics used by major technical agencies.

Useful links

Shearwater dive computers
Faber steel cylinders
All Simple Dive articles

Maximum Operating Depth (MOD)

Oxygen (%): PPO₂:

MOD: 33.8 m

Typical planning: PPO₂ 1.2–1.4 for working dives, up to 1.6 for decompression.

Optimal Oxygen Fraction for Target Depth

PPO₂: Target depth (m):

Optimal O₂: 35.0%

Gas Density with Helium

Depth (m): O₂ (%): He (%): Temperature (°C):

Density: 5.24 g/L

Recommended: <5.2 g/L for working dives; avoid >6.2 g/L because of increased work of breathing and CO₂ retention.

Equivalent Air Depth (Trimix)

O₂ + He ≤ 100%

O₂ (%): He (%): Depth (m):

EAD (N₂ narcotic): 30.0 m

EAD (N₂ + O₂ narcotic): 30.0 m

N₂ model assumes only nitrogen is narcotic. N₂ + O₂ model assumes both nitrogen and oxygen contribute to narcosis.

SAC Rate Calculator

Cylinder volume (L): Pressure drop (bar): Average depth (m): Dive time (min):

SAC: 15.0 L/min

Disclaimer: Planning tool only. Always confirm results with a dive computer and a qualified instructor. Never dive beyond your training or comfort level.