In Genesis, how many years after Noah was 600 did the flood begin?

The flood began in the same year that Noah was 600 years old.

Genesis 7:6 states that Noah was 600 years old when the floodwaters came upon the earth. This can be compared with Genesis 7:11, which dates the beginning to the seventeenth day of the second month of Noah’s six-hundredth year. The two references identify the same year, not separate stages a year apart.

The wording is easy to confuse with the ages of 500 and 950. Noah was 500 when Genesis introduces the births of Shem, Ham, and Japheth, while Genesis 9:29 records that he eventually lived 950 years. Neither figure marks the flood’s beginning.

This chronological detail is a precise internal cross-reference in the flood narrative. It does not mean the flood lasted only one year; Genesis separately describes rainfall, prevailing waters, recession, and the eventual departure from the Ark.