Male human brains are about 10 percent heavier than female brains.

Across large-scale population studies and autopsy data, adult male human brains weigh roughly 10% to 12% more than adult female human brains:

Average Adult Male Brain: ~1,335 to 1,375 grams (~2.95 lbs)

Average Adult Female Brain: ~1,200 to 1,250 grams (~2.65 lbs)

Key Context:

Body Size Proportions: This absolute difference in weight is almost entirely driven by general differences in total body size and height between sexes. Larger bodies require larger neural structures to manage basic motor and sensory functions.

No Impact on Intelligence:

Absolute brain size within a species does not correlate with cognitive ability or intelligence. Female brains offset the mass difference with higher neuronal density in certain areas, higher proportions of gray matter relative to white matter, and greater cortical thickness.

Even the smallest brains can be remarkably complex and effective. Think of an ant. They can coordinate six legs, make decisions about where to go based on scent and other factors, know how to carry food back to the colony, and do all the things ants need to do, yet their brains are tiny specks.