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Calcimator

Nitrox Blend Calculator

Calculate Maximum Operating Depth (MOD), Equivalent Air Depth (EAD), best mix, and oxygen toxicity limits for Nitrox/EANx diving.

Inputs

%

Results

MOD (metres)

33.8

MOD (feet)111
EAD (metres)24.4
EAD (feet)80
ppO2 at depth1.28
Best mix for depth (%)35
CNS O2 limit (min)210
How to Use This Calculator
  1. Enter the oxygen percentage of your Nitrox blend (e.g., 32% for EAN32 or 36% for EAN36).
  2. Input your planned maximum depth in meters.
  3. Set your ppO2 limit: 1.4 bar for bottom gas, 1.6 bar for decompression stops.
  4. Read MOD (Maximum Operating Depth) in meters and feet — never dive deeper than this on the blend.
  5. Check EAD (Equivalent Air Depth) to use air dive tables for decompression planning.
  6. Review Best Mix for Depth to see the optimal O2 percentage for your planned depth at your ppO2 limit.

How the result changes with Oxygen fraction (%)

Oxygen fraction (%)MOD (metres)
2350.9
2840
3332.4
3826.8

What each input means

Oxygen fraction (%)
Oxygen percentage in the Nitrox blend (EANx). Common mixes: EAN32, EAN36.
Planned depth (m)
Maximum planned depth in metres for EAD and ppO2 calculations.
ppO2 limit (bar)
Maximum partial pressure of oxygen. Recreational limit is 1.4 bar (1.6 for deco).

What each result means

MOD (metres)
Maximum Operating Depth where ppO2 reaches your set limit.
MOD (feet)
Maximum Operating Depth in feet.
EAD (metres)
Equivalent Air Depth — the air-dive depth with the same nitrogen narcosis risk.
EAD (feet)
Equivalent Air Depth in feet.
ppO2 at depth
Partial pressure of oxygen at your planned depth.
Best mix for depth (%)
Optimal O2 percentage for the entered depth at your ppO2 limit.
CNS O2 limit (min)
Approximate single-exposure CNS oxygen toxicity time limit (NOAA).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    Oxygen fraction (%) = 32, Planned depth (m) = 30, ppO2 limit (bar) = 1.4 = 3 input(s) provided
  2. Calculate MOD
    MOD = (ppO2max / fO2 - 1) * 10
    33.8 = 33.8
  3. Calculate MOD
    MOD = modM * 3.281
    111 = 111
  4. Calculate EAD
    EAD = Math
    24.4 = 24.4

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