An average adult human brain weighs about 1.3–1.4 kg , which is roughly 3 pounds.

Basic brain weight facts

  • Typical adult range: about 1,200–1,400 grams (1.2–1.4 kg).
  • Often rounded in everyday explanations as “about 3 pounds.”
  • The brain makes up roughly 2% of total body weight in adults.

Differences and variation

  • Average male brain: around 1,330–1,370 g ; average female brain: around 1,200 g.
  • Newborn baby brains are much lighter, usually about 350–400 g.
  • There is natural variation between healthy people, so there is no single “perfect” number.

Fun context

  • The cerebrum (the big wrinkled part) accounts for most of that weight, about 85% of the total.
  • Despite its small share of body mass, the brain uses a large share of blood flow and energy, highlighting how demanding this organ is.

Information gathered from public forums or data available on the internet and portrayed here.