Chronology

The standard Masoretic text of the Hebrew Bible places Abraham's birth 1,948 years after the Creation, or 1948 AM (Anno Mundi, "Year of the World"). The two other major textual traditions have different dates, the translated Greek Septuagint putting it at 3312 AM and the Samaritan version of the Torah at 2247 AM. All three agree that he died at the age of 175. There have been over two hundred attempts to match the biblical chronology to dates in history, two of the more influential being the traditional Jewish dates (Abraham lived 1812 BCE to 1637 BCE), and those of the 17th century Archbishop James Ussher (1976 BCE to 1801 BCE); but the most that can be said with some degree of certainty is that the standard Hebrew text of Genesis places Abraham in the earlier part of the second millennium BCE.
 

Abraham - Historicity and origins