THIS MIGHT SURPRISE YOU
The answer
About a year — a year and ten days, precisely. The flood begins in Noah's six hundredth year, second month, seventeenth day (Genesis 7:11), and the earth is dry in his six hundred first year, second month, twenty-seventh day (8:14).
Why it’s interesting
The story dates itself like a ship's log: when the ark grounds, when the mountaintops appear, when the ground dries. Nursery versions keep the forty days; the text keeps a full calendar.
Scholarly consensus
You can know the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.