The cerebral cortex makes up 80% of the brain. True or false?

False. In humans the cerebral cortex makes up 77% of our brains (by volume).

There are about 86 billion neurons and 85 billion glial cells in the human male brain ... In humans the cerebral cortex makes up 77% of brain by volume. The cerebellum adds another 10%. The diencephalon, midbrain and hindbrain make up about another 10%.