Short answer: 8 people
Bible reference: Genesis 7:13
“In the selfsame day entered Noah, and Shem, and Ham, and Japheth, the sons of Noah, and Noah’s wife, and the three wives of his sons with them, into the ark.”
The Bible calls Noah “a preacher of righteousness” [2 Peter 2:5]. Noah tried to warn others about God’s coming judgment for sin, but no one listened. The door of the Ark was open to anyone who wanted to be saved, until the day the rain came and God shut the door of the Ark. They ignored Noah’s warnings until it was too late. Everyone on the Ark was saved. Everyone outside the Ark died.
Only Noah, his wife, his three sons and their wives were safe on the Ark. Except these 8 people [1 Peter 3:20], every other person died.
Just like then, preachers are warning people of God’s judgment for sin, the bad things we do when we know not to and the good things we fail to do when we know we should. And just as there was a Door on the Ark people could enter and be saved, there is a Door of Salvation today. That Door is Jesus Christ. Jesus is the only name under heaven and earth by which men must be saved. There was only one Door to the Ark; there is only one way to be saved from the judgment of our sin.
Ask Jesus to save you from your sins today, while the Door is still open.