King Tutankhamun rose to the throne when he was just a boy in 1332 B.C. (or 1336 B.C. by some accounts) and ruled Egypt until his death in 1323 B.C. He was born around 1341 B.C.
The four-year disparity concerning Tutankhamun's accession date is due to a difference in how pharaohs are accounted by Egyptologists. New pharaohs were often raised up to be co-regents to their predecessors, acting as a sort of vice-regent or pharaoh-in-training until the old pharaoh died. New pharaohs were given all the titles of a senior pharaoh, so it is often difficult to determine how long co-regent pharaohs really ruled. During 1336 B.C. and 1332 B.C., Tutankhamun seems to have been junior co-ruler to a more mysterious figure, the pharaoh Smenkhkare. Deliberately destroyed records make it difficult to pin down Tutankhamun's true accession date.