Working out an oxygen plan for Everest: how many bottles, and how long does one last?
How many oxygen bottles do I need, and at what flow?
Most climbers use at least four to five bottles per attempt. A 4-litre bottle at 250 bar lasts about 8 hours 20 minutes at 2 litres a minute; plan for up to 18 hours of oxygen on summit day.
The full answer, kept up to date: How many oxygen bottles do I need on Everest? The guide chapter: Supplementary oxygen