How large is the human heart?

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Illustration of a human heart cross-section showing four chambers-left and right atria and ventricles-with labeled major blood vessels. An inset highlights cardiac muscle tissue, showing myocytes and intercalated disks. — human cardiovascular system The human heart is both a pump and a muscle. Its four chambers move blood efficiently, while cardiac muscle cells joined by intercalated disks synchronize each contraction.

The adult human heart is typically described as being slightly larger than a clenched fist. Its dimensions are approximately 12 to 13 cm (5 inches) in length, 8 to 9 cm (3.5 inches) in width, and 6 cm (2.5 inches) in thickness.12

The heart generally weighs between 250 and 350 grams (9 to 12 ounces), though these measurements can vary depending on an individual's body size and sex.21