Calculators / Partial pressure and mixes

Topping up a gas bank calculator

The pressure to top a bank up to with a second gas, to bring it to the oxygen percentage you want.

Topping up a bank

Final = start x (start% - add%)/(final% - add%)

METRIC

Start pressure (bar)Start O2 %Added gas O2 %Final O2 %

The formula: Final = start x (start% - add%)/(final% - add%). Change any box and the full working updates. For study only, never for dive planning.

Practise it the way the exam asks it

The IMCA ADS, BDS and LST papers ask this as a four-option question, with a calculator on screen. A free account gives you 15 practice questions for each exam, each with the worked answer and the document it comes from.

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