Unfortunately, Ussher gets most of the credit; Lightfoot's contribution is rarely cited.
This would make the time interval between the creation of the world and a common estimate of the birth of Christ (4 to 7 BCE) to be close to 4000 years.
Since then, estimates have been refined; almost all have grouped around 14 billion years.
Currently, there is a near consensus among earth scientists that the age of "Earth and [the rest of] our solar system is 4.54 billion years, plus or minus 0.02 billions years." Both values are in conflict with interpretations of the biblical accounts of creation by "young earth" creationists.
Ussher dated the arrival of Abraham in Canaan to 2126 BCE and the Noachian flood at 2349 BCE.
The latter is unlikely, because historical records in both China and Egypt continued without disruption through that date, and contain no record of a massive world-wide flood that would have wiped out their civilizations.
The earliest event in the Bible that can be dated with reasonable certainty is the beginning of Saul's reign as the first king of Israel.