If you don’t have access to the calculator above simply use the following formula to calculate the minutes remaining in your oxygen tank:

Here’s what you will need:

- Tank size & conversion factor for that tank
- PSIG (amount of pressure remaining in the tank)
- Flow rate (LPM)

**Formula:** Minutes remaining = PSIG * Tank conversion factor/Flow rate

Tank Size | Conversion factor |

E | 0.28 |

D | 0.16 |

H | 3.14 |

M | 1.56 |