Nitrogen Narcosis & END Calculator
Calculate Equivalent Narcotic Depth, partial pressures, MOD and narcotic load for air, Nitrox and trimix.
Understand the narcotic load.
Choose a gas and depth. This model treats oxygen and nitrogen as narcotic and helium as non-narcotic when calculating Equivalent Narcotic Depth.
What Equivalent Narcotic Depth represents
Equivalent Narcotic Depth estimates the depth at which a reference gas would produce a similar narcotic-gas partial pressure. The result changes with actual depth and with which gases are treated as narcotic by the selected model.
Example: when a breathing mix contains less narcotic gas than air, its calculated equivalent narcotic depth can be shallower than the actual depth. The number is a comparison tool rather than a prediction of how a specific diver will feel.
Narcosis varies greatly between divers and conditions, and models differ on the narcotic contribution of oxygen and other gases. END does not establish a safe depth and must not replace training, experience or appropriate gas planning.
The calculator updates instantly from the values you enter and shows the core planning result in the dark result card.
Use realistic values from your own diving and leave a practical margin for changes in workload, conditions and equipment.
Treat this page as an educational reference and cross-check the result with your training, analysed gas and an appropriate dive-planning method.