How many years after Noah's birth did Genesis say the flood came?

Genesis says the flood came when Noah was 600 years old, or 600 years after his birth.

Genesis 7:6 states that Noah was six hundred years old when the floodwaters came upon the earth. The same chapter gives the flood's starting date as the seventeenth day of the second month, linking Noah's age with the calendar chronology.

This number is not the same as Noah's total lifespan. Genesis 9:29 says that Noah lived 950 years in all, meaning he lived another 350 years after the flood. Confusing these two figures changes the meaning of the chronology.

The age also differs from the age at which Noah's sons are mentioned. Genesis introduces Shem, Ham, and Japheth before the flood, but it does not state that they were all the same age or born in a particular order. The clear figure for the flood is Noah's age: 600.