How the Oxygen Converter Works
The Oxygen Converter divides oxygen mass by gas density at the stated conditions. The default 0.001331 kg/L (1.331 kg/m³) fits oxygen gas at 20°C (68°F) and 1 atm.
Enter the oxygen mass
Type the O₂ mass in kilograms, such as the weight difference of a full and empty cylinder.
Keep the gas density
Use 1.429 kg/m³ at 0°C or 1.331 kg/m³ at 20°C.
Read the gas liters
The result gives free gas volume at 1 atm.
Check cylinder sizes
Use the table to convert medical and industrial cylinder contents.
Oxygen Converter Formula
The oxygen formula is Vgas = m ÷ 1.331 kg/m³ at 20°C. Liquid oxygen (LOX) at 1.141 kg/L expands about 857 times into gas.
- 1.331
- O₂ gas density at 20°C, 1 atm, kg/m³
- 1.141
- Liquid oxygen density at −183°C, kg/L
Worked Examples
- 1 kg of O₂: 1 ÷ 0.001331 = 751 L of gas.
- E cylinder (680 L): 680 × 1.331 ÷ 1,000 = 0.905 kg of oxygen.
- Patient at 2 L/min: 680 L ÷ 2 = 340 minutes (5.7 hours).
Oxygen Converter Conversion Table
1 kg of oxygen gas fills 751 liters at 20°C. The table lists oxygen in medical and industrial cylinders.
| Cylinder | Gas Volume (L) | O₂ Mass (kg) | LOX Equivalent (L) | Duration at 2 L/min |
|---|---|---|---|---|
| M6 / B | 165 | 0.220 | 0.192 | 1.4 h |
| D | 425 | 0.566 | 0.496 | 3.5 h |
| E | 680 | 0.905 | 0.793 | 5.7 h |
| M60 | 1,700 | 2.263 | 1.983 | 14.2 h |
| G | 5,300 | 7.054 | 6.183 | 44.2 h |
| H / K | 6,900 | 9.184 | 8.049 | 57.5 h |
| J | 6,800 | 9.051 | 7.932 | 56.7 h |
| LOX dewar (1 L liquid) | 857 | 1.141 | 1.000 | 7.1 h |
What is an Oxygen Converter?
An Oxygen Converter is a calculator that converts oxygen mass into gas volume at a set temperature and pressure.
Oxygen (O₂) is 20.95% of dry air by volume. Industrial oxygen comes from cryogenic air separation units that distill liquid air at about −190°C.
Oxygen is heavier than nitrogen: 1.331 kg/m³ against 1.165 kg/m³ at 20°C. Medical oxygen must reach 99.5% purity under the European and US pharmacopoeias.
What are the Uses of an Oxygen Converter?
There are 4 main uses of an Oxygen Converter.
Medical oxygen
Clinicians convert cylinder contents into treatment time.
Welding and cutting
Fabricators convert bulk O₂ deliveries into gas volume.
Aquaculture
Fish farms dose oxygen into ponds by mass.
Water treatment
Plants convert LOX tanks into gas supply days.