The average adult human brain weighs approximately 3 pounds (1300-1400 grams) and measures about 5.5 x 6.5 x 3.6 inches (140 x 167 x 93 mm). However, this is just an average; brain size varies between individuals.
Brain Size Across Life Stages
- Adult: The average adult brain weighs around 3 pounds (1300-1400 grams).
- Newborn: A newborn's brain weighs significantly less, approximately three-quarters of a pound (350-400 grams).
- Full Development: Brain development continues until around age 25.
Brain Size Comparisons
To put the size in perspective, the human brain is roughly the size of a grapefruit or about the volume of ten tennis balls. (Ask An Anthropologist)
Factors Affecting Brain Size
While the average size is well-established, individual variations exist. Factors influencing brain size include genetics, nutrition, and overall health. Further research is continually expanding our understanding of brain size and its correlation with cognitive abilities. It's important to remember that brain size alone doesn't determine intelligence or cognitive function.
Additional Considerations:
While this answer focuses on human brain size, it's important to note that brain size varies greatly across species. For example, domesticated dogs show significant differences in brain size across breeds. (Brain weight predicts yawn duration across domesticated dog ...)
