Gas instrument

Nitrox & gas

Best mix for a depth, MOD for a mix, and a partial-pressure blend estimate. A planning aid — verify your fills with an analyser.

About this tool

Works out safe nitrox mixes and depths, plans a partial-pressure blend, and analyses a mix you've already made.

Mix & depth: enter a depth to get the best mix, or a mix to get its MOD and ppO₂.
Blend — recipe: enter a target mix and fill to get how much O₂ then air to add.
Analyzer: enter what you added to see the resulting mix and its MOD.

Mix & depthWorking ppO₂ limit

What mix for my depth?

Planned depth (m)

✓ Best mix at 30 m is EAN35 (richest blend within ppO₂ 1.4).

What depth for my mix?

Mix O₂ %

MOD @1.4

34 m

MOD @1.6

40 m

ppO₂ here

1.28

EAD

24 m

✓ EAN32 is good to 34 m at ppO₂ 1.4.

Blend — recipe

Estimate to reach a target mix by adding pure O₂ then topping with air.

Start pressure (bar)Start O₂ %Final pressure (bar)Target O₂ %

Add O₂

27.8 bar

Then air to

200 bar

(air added)

172.2 bar

✓ Reaches EAN32 at 200 bar — add 27.8 bar O₂, then air to 200.

Partial-pressure estimate, air = 21% O₂. Always analyse the finished mix.

Analyzer — what did I get?

Enter what you added; see the resulting mix and its MOD.

Start pressure (bar)Start O₂ %O₂ added (bar)Air added (bar)

Result

33% O₂

Final

200 bar

MOD @1.4

33 m

MOD @1.6

39 m

✓ You mixed EAN33 at 200 bar — MOD 33 m (ppO₂ 1.4).

Estimate only — always analyse the finished mix with an O₂ analyser.

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