Factual error: In the bus scene in Nepal when Krakauer is telling Weathers how Doug Hansen is actually an experienced climber, he boasts that Hansen has already been on Everest, adding Long's Peak and Mount McKinley as two other major mountain feats this mere mailman has also conquered. This is ridiculous. First, Krakauer, an experienced mountaineer, would be using Mount McKinley's proper name, Denali. Second, Long's Peak isn't even in the same category as McKinley and Everest. That the screenwriters even mention Long's in the same sentence as the other two is flabbergasting. Long's Peak is located in Estes Park, Colorado and is basically a ten-hour round-trip hike that doesn't even require ropes. It's so easy that children, seniors, and even dogs summit Long's all the time with nothing but water in tow. (00:06:50)
Factual error: In different shots of the movie you see the characters warming their hands with their breath; which in real life would be an absolute no go, as the humidity of the breath will make the hands wet and colder/frozen. Also, when most characters reached the "death zone" they were not out of breath and spoke sentences too long for the shortage of oxygen on that altitude.Shakura Sharkademus
Other mistake: The scene at night after the storm ends, they wake up and the time is shown at the bottom of the screen of 00:30am, ie. 24 hour time. Another night later on in the film, the time is shown as 12:30am.
Continuity mistake: When the team is crossing the crevasse on the ladder bridge at the ice fall. For safety, the climbers are tethered from their harnesses to the rope handrails with another short length of rope attached to a carabiner clip on each side. As Josh Brolin is crossing, you can see his tether, which he pushes along in front of his hands as he progresses. However, when the camera cuts to a reverse close-up from below, the tether has suddenly disappeared. When the shot cuts wide again, the safety tether has returned. (00:28:15)