Gas Blending Calculator

Gas Blending — Key Features

• Nitrox blending with partial pressure method
• Trimix blending — O₂, He, and air calculations
• Step-by-step fill instructions with exact pressures
• Support for starting with partially filled tanks
• Clear warnings for safety limits and equipment compatibility
• Works with both metric (bar) and imperial (PSI) units

Gas Blending — How It Works

Enter your current tank pressure and gas mix, then specify your target pressure and desired mix. The calculator determines exactly how much pure oxygen (and helium for trimix) to add, followed by an air top-up to reach the final pressure. Each step shows the exact pressure to fill to.

Why Use Our Blending Calculator?

• Precise partial pressure calculations every time
• Clear step-by-step instructions reduce blending errors
• Supports both nitrox and trimix blending
• Accounts for existing gas in partially filled tanks

Gas Blending — Frequently Asked Questions

What blending method does this calculator use?

It uses the partial pressure method: first add pure oxygen to increase O₂ content, then optionally add helium (for trimix), and finally top up with air to reach the target pressure.

Can I blend starting from a partially filled tank?

Yes. Enter your current tank pressure and mix, and the calculator will account for the existing gas when calculating the fill sequence.

Is blending training required?

Yes — gas blending should only be performed by trained personnel using blending-compatible equipment. Always verify the final mix with an oxygen analyzer before diving.

What gas mixes can I blend?

You can blend any nitrox mix (21-100% O₂), trimix (oxygen, helium, and nitrogen), or heliox (oxygen and helium only). The calculator supports standard recreational nitrox up to advanced technical trimix blends.

How do I verify the final mix?

Always analyze your final mix with a calibrated oxygen analyzer before diving. For trimix, also use a helium analyzer. The calculator provides target values, but actual results may vary slightly due to temperature and mixing effects.

Does temperature affect blending calculations?

Yes. Gas compresses differently at various temperatures, which can affect the final mix. For best results, let your tank equalize to ambient temperature before analyzing. The calculator assumes standard conditions, so small deviations are normal.