Harold Camping has convinced his followers that the end of the world is Saturday, May 21, 2011.  Here is how he interpreted the Bible to arrive at that date.

Camping believes the rapture is simply 7,000 years after Noah’s flood.

Genesis 7:6 – 10

Noah was six hundred years old when the floodwaters came on the earth. And Noah and his sons and his wife and his sons’ wives entered the ark to escape the waters of the flood. Pairs of clean and unclean animals, of birds and of all creatures that move along the ground, male and female, came to Noah and entered the ark, as God had commanded Noah. And after the seven days the floodwaters came on the earth.

He gets the 7 from the verse above.

2 Peter 3:8

But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.

He cites the scripture above to convert 7 days to 7,000 years.

Will May 21 Doomsday, Judgment Day really happen? Vote, Discuss, Countdown

Camping dates the flood at 4990 BC.

From biblehistory.net

1 Kings 6:1 states that Solomon began building the Temple in the fourth year of his reign, 480 years after the Exodus.  Most bible scholars agree that the fourth year of Solomon's reign was 967 B.C.   So the date of the Exodus can be calculated: 967 + 480 = 1447 B.C.

He uses 1447 B.C. as the date of the Exodus.

The bible lists the genealogy (birth and how many years they lived) of the patriarchs and the Israelites. For example, Adam, born on the first year of creation, lived 930 years, so his death marks 930 years since creation.

Using the Bible’s genealogy, Camping went from 1447 B.C. all the way back to Noah and backed out the date of the flood (which occurred when Noah was 600 years old) to be 4990 B.C.  Then,  4990 B.C. + 7001 = 2011 A.D.

Genesis 7:11

In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.

In the Hebrew Calendar, the 17th day of the 2nd month is May 21, 2011.