Silverback gorillas, which are mature adult male gorillas, typically stand upright at heights ranging from about 5 feet (1.5 meters) to around 6 feet (1.8 meters). Most sources indicate an average height of approximately 5.5 to 5.9 feet (1.7 to 1.8 meters) when standing fully upright, though some can reach up to 6 feet tall or slightly more

. In summary:

• Common height range standing upright: 5 to 6 feet (1.5 to 1.8 meters)
• Some individuals recorded up to 6.6 feet (2 meters) or taller in rare cases

This variation depends on the individual gorilla and subspecies, but generally, silverbacks are comparable in height to tall adult humans when standing upright.