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Gas Blender Calculator

Partial-pressure blending instructions for Nitrox and Trimix fills — from empty or from a cylinder with residual gas.

Fill Parameters
L

Enter parameters and press Calculate Blend.

Cylinder Status
L
Desired Final Mix

Enter cylinder status and desired mix, then press Calculate Top-Up.

Partial-Pressure Blending Notes
  • Fill order for safety: Always add Helium first, then Oxygen, then top up with Air. This minimizes the risk of oxygen-rich mixtures at high pressure.
  • Oxygen cleanliness: Equipment used for oxygen partial pressures above 40% must be O₂-cleaned and rated for oxygen service.
  • Pressure tolerance: Real fills have a ±2 bar tolerance. The values shown are ideal targets.
  • Analyzing fills: Always analyze your mix with a calibrated O₂ analyzer (and He analyzer for Trimix) before diving.
  • Regulations: Gas blending must be performed by trained and certified gas blenders. Follow all applicable regulations and your agency's guidelines.