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Calcimator

Trimix Blend Calculator

Calculate MOD, Equivalent Narcotic Depth (END), partial pressures, and hypoxic safety for Trimix gas blends used in technical deep diving.

Inputs

%
%

Results

MOD (metres)

56.7

END (metres)

35.5

MOD (feet)186
END (feet)116
Nitrogen (%)44
ppO2 at depth1.47
ppN2 at depth3.08
ppHe at depth2.45
Hypoxic at surface?0
Min switch depth (m)0
How to Use This Calculator
  1. Enter the oxygen percentage in your Trimix blend (e.g., 21% for normoxic, lower for hypoxic mixes).
  2. Input the helium percentage — helium replaces nitrogen to reduce narcosis at depth.
  3. Set your planned maximum depth in meters.
  4. Set your ppO2 limit in bar (1.4 for bottom gas, 1.6 for decompression).
  5. Read MOD in meters to confirm your dive plan stays within safe oxygen limits.
  6. Check END (Equivalent Narcotic Depth) in meters — ideally keep END below 30 m to minimize narcosis risk.
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