The human brain weighs about 3 pounds (approximately 1,300 to 1,400 grams) and has a volume of around 1,300 cubic centimeters, roughly the size of ten tennis balls
. On average, adult male brains weigh about 1,345 grams with a volume near 1,260 cm³, while adult female brains weigh about 1,222 grams with a volume near 1,130 cm³, though there is considerable individual variation
. The brain makes up about 2% of total body weight and is composed of roughly 86 billion neurons
. Its largest part is the cerebral cortex, which is highly folded to fit a large surface area into a compact space, playing a key role in complex functions like thought, perception, and language
. In comparison to other animals, humans have relatively large brains for their body size, which is notable even though some animals like elephants have larger brains by weight
. The human brain volume peaks in the teenage years and tends to decline after age 40
. In summary, the human brain is about 1,300–1,400 grams in weight and around 1,300 cubic centimeters in volume, making it one of the largest and most complex brains among mammals relative to body size
