Oxygen Duration Calculator Full cylinder assumed How long will youroxygen last? Choose your cylinder. Select your flow. See your estimate. 01 Choose your cylinder B (M6) / 170 L C (M9) / 255 L D / 425 L E / 680 L Cylinder size / full oxygen capacity 02 Select your flow rate 2liters / minute 1 L/min15 L/min Adult continuous-flow regulator · 1–15 L/min ◷ESTIMATED DURATION About 5 hr 40 min 340minutes total Full E cylinder · 2 L/min Full-to-empty estimate. No safety reserve included. Enable JavaScript to update the estimate.