The approximate brain weight of an adult elephant is 5 kilograms.
That figure is an average rather than a fixed limit. Published measurements commonly place adult elephant brains around 4.5–5 kilograms, with variation by species, sex, and individual. One anatomical study reported an adult average of about 4,783 grams.
An elephant’s brain is the largest among living terrestrial mammals in absolute mass, weighing roughly three to four times as much as a human brain. Yet size alone does not measure intelligence: because an elephant’s body is enormous, its brain is proportionally smaller than a human brain.
The elephant brain is notable for its developed cerebrum and cerebellum and especially large temporal lobes. Those structures are associated with complex sensory processing, learning, memory, and social behaviour. The “5 kg” answer is therefore an appropriate rounded estimate, not a claim that every adult elephant has exactly that weight.