An average house cat’s brain is quite small: it’s about 5 centimeters (around 2 inches) long, weighs roughly 25–30 grams (about 1 ounce), and is often compared to the size of a large walnut or a human pinky finger. For most adult cats, that works out to around 1% of their total body weight, which is a smaller proportion than in humans, whose brains are a bit over 2% of body weight.
Basic size and weight
- Length: about 5 centimeters / 2 inches from front to back.
- Weight: roughly 25–30 grams (0.88–1.06 ounces).
- Body percentage: about 0.9–1% of the cat’s body mass.
How that compares to humans and dogs
- Humans: the brain is a bit over 2% of body mass, so a cat’s brain is smaller both in absolute size and as a percentage of body weight.
- Dogs: a dog’s brain is larger (often likened to a tangerine), while a cat’s is closer to a walnut, though intelligence depends more on structure and neurons than sheer size.
What’s inside that small brain
Even though it is small, a cat’s brain is highly folded and complex, with an outer cortex similar in layout to a human’s and containing around 200–300 million neurons, supporting good memory, problem solving, and coordination.
