How much time passes between Adam and Jesus?

It's not that hard to calculate based on the Bible's own records. However, one must understand that the Bible does throw a few math problems our way, and presents much of the timeline in historical records and prophecies, especially the latter.

The First 20 Generations

The first 20 generations are given us explicitly.

The capitalized names are special cases: Enoch did not die, but was taken to heaven; Noah's sons require just a little math because they were not actually triplets; and Terah's sons likewise were not triplets and require a little math. In the case of Noah, his firstborn, Japheth, was born when Noah was 500, but the birthright son, Shem (who gets listed first), was born when Noah was 502--calculated from the fact that at the time of the Flood, Noah was 600, and Shem was only 98 because he had his son Arphaxad when he was 100, two years after the Flood. In the case of Terah, Abram is also listed first, being the birthright son, while actually sixty years younger than Terah's eldest--calculable by the fact that when Terah dies, Abram is said to be 75 years old.

These first 20 generations take us about 2000 years into earth's history. I say "about" because there may very well have been some rounding--as a careful study of the times of the kings will illustrate. Essentially, a partial year would count as a full year, so if one were (by our calendar) born in December and died in January, nearly two full years could be added.

Prophetic / Historical Times

From the time of Abraham onward, most of our timeline is based on historical records and/or prophecies. These can be somewhat corroborated by generation/regency data, but this information is of secondary quality, and incomplete.

Naturally, this is an estimate. The times are likely rounded up in places, never down. Particularly for the first 20 generations, which have no direct historical record or prophecy spanning them, it is reasonable to subtract about 20 years, which amounts to the average possible rounding for that period (minimum being zero, maximum being 40--with neither extreme very plausible). The other periods, such as Abraham's family spending 430 years in Egypt, 400 years of which was in affliction and in bondage, denoting times of persecution followed by a time of slavery, are more precise, with Exodus 12:40 informing us that on the very day of the fulfillment of that prophecy, the children of Israel departed from Egypt. Prophecies are exact, no rounding.

The times of the judges are very sketchy, but they are superseded by 1 Kings 6:1--a scribal record of the years from the Exodus to the time of Solomon's reign which is precise down to the month. From the time of Rehoboam (Solomon's son, king of Judah and Benjamin) and Jeroboam (king of the ten tribes), the prophecy in Ezekiel 4, spanning 390 years, indicates the precise time until the destruction of Solomon's temple. So all the questions about the accuracies of the times of the kings can be superseded by prophetic time, which is reliable.

From the end of the Babylonian captivity until the start of Daniel's prophecy there is a small margin for error, plus or minus a few decades. Extra-biblical historical records, however, can help fill in those blanks.

Conclusion

The maximum time, without correcting for rounded years in Genesis or improved calculations during the time of Daniel, from Creation until Jesus' birth, comes out to almost precisely 4000 years. After corrections, this figure must be reduced. It is possible that Jesus' death occurred at about the 4000-year mark. It is not possible that Jesus could have been born after the 4000-year mark.

As other answers have indicated, we cannot know the exact time. However, these figures should help us understand that we are not that far off from knowing it...it's not a total gray area. We can come within a few years of the actual figure.

How much time passes between Adam and Jesus?

This is impossible to determine with any certainty or accuracy, however many hold that some 4,000 years passed between the creation of Adam to the birth of Jesus. The year 4004 Anno Mundi is the most acceptable year so far.

Septuagint

Many of the earliest Christians who used the Septuagint version of the Bible calculated creation as having occurred about 5500 BC, and Christians up to the Middle-Ages continued to use this rough estimate: Clement of Alexandria (5592 BC), Theophilus of Antioch (5529 BC), Sextus Julius Africanus (5501 BC), Hippolytus of Rome (5500 BC), Gregory of Tours (5500 BC), Panodorus of Alexandria (5493 BC), Maximus the Confessor (5493 BC), George Syncellus (5492 BC), Sulpicius Severus (5469 BC) and Isidore of Seville (5336 BC). The Byzantine calendar has traditionally dated the creation of the world to September 1, 5509 BC.

The Chronicon of Eusebius (early 4th century) dated creation to 5228 BC while Jerome (c. 380, Constantinople) dated creation to 5199 BC. In the Roman Martyrology, the Proclamation of the Birth of Christ formerly used this date, as did the Irish Annals of the Four Masters.

Bede was one of the first to break away from the standard Septuagint date for the creation and in his work De Temporibus ("On Time") (completed in 703 AD) dated the creation to 18 March 3952 BC but was accused of heresy at the table of Bishop Wilfrid, because his chronology was contrary to accepted calculations of around 5500 BC.

Masoretic

After the Masoretic Text was published, however, dating creation around 4000 BC became common, and was received with wide support. Proposed calculations of the date of creation using the Masoretic from the 10th century to the 18th century include: Marianus Scotus (4192 BC), Henry Fynes Clinton (4138 BC), Henri Spondanus (4051 BC), Benedict Pereira (4021 BC), Louis Cappel (4005 BC), James Ussher (4004 BC), Augustin Calmet (4002 BC), Isaac Newton (3998 BC), Petavius (3984 BC), Theodore Bibliander (3980 BC), Johannes Kepler (April 27, 3977 BC) [based on his book Mysterium Cosmographicum], Heinrich Bünting (3967 BC), Christen Sørensen Longomontanus (3966 BC), Melanchthon (3964 BC), Martin Luther (3961 BC), Cornelius Cornelii a Lapide (3961 BC), John Lightfoot (3960 BC), Joseph Justus Scaliger (3949 BC), Christoph Helvig (3947 BC), Gerardus Mercator (3928 BC), Matthieu Brouard (3927 BC), Benito Arias Montano (3849 BC), Andreas Helwig (3836 BC).

Among the Masoretic creation estimates or calculations for the date of creation only Archbishop Ussher's specific chronology dating the creation to 4004 BC became the most accepted and popular, mainly because this specific date was attached to the King James Bible.

Polish Christmas carol Wśród nocnej ciszy contains text Cztery tysiące lat wyglądany (Looked out for four thousand years) related to Jesus, which also corresponds to date of creation based on Masoretic Text.

Alfonsine tables

Alfonso X of Castile commissioned the Alfonsine tables, composed of astronomical data based on observation, from which the date of the creation has been calculated to be either 6984 BC or 6484 BC.

• Other biblical estimations

In 1738, Alphonse Des Vignoles said he had collected over 200 different estimates, ranging from 3483 BC to 6984 BC. John Clark Ridpath attributes these values respectively to Yom-Tov Lipmann-Muhlhausen and Regiomontanus.

• Christian Charles Josias Bunsen in the 19th century dated the creation to 20,000 BC.

• Tarleton Perry Crawford dated the creation to 12,500 BC.

• Harold Camping dated the creation to 11,013 BC.

Dating creation

The elapsed time from Creation to Incarnation depends on the chosen options regarding 4 issues:

1. The textual tradition: Masoretic Text (MT) or Septuagint (LXX).

2. The age at which Terah begot Abraham: 70 or 130 years.

3. The time elapsed since Jacob's entry into Egypt to the Exodus: 215 or 430 years.

4. The year of Jesus' birth: from 7 BC to 1 BC.

In the case of the LXX there are two additional issues: whether or not to include the 2nd Cainan (who is in Luke's genealogy) and whether or not to correct Methuselah's begetting age from 167 to 187 years so as to avoid his outliving the Flood 14 years. The range of additional years of the elapsed time with respect to that from the MT is between these two cases:

• No Cainan 2, Methuselah begets at 167 (Eusebius' Chronicon): MT + 1236

• Cainan 2, Methuselah begets at 187 (Codex Alexandrinus): MT + 1386

A very good introduction to issues 2 & 3 and links to further bibliography can be found in [1], together with the 8 chronologies, 4 from Usher and 4 from Thiele, which result from the combinations of options.

As can be seen in [1], the Usher and Thiele chronologies agree on the set of 4 AM years of beginning of construction of the First Temple and disagree on the only BC year, which for the Usher chronologies is 1012 BC and for the Thiele chronologies is 967 BC. At present, scholars agree almost unanimously that the Thiele chronology of BC dates till Solomon is correct.

The following table gives the BC year of Creation in each of the Thiele chronologies that result from each combination of choices on issues 2 and 3.

------------+--------------+-------------+
Abraham's   | Israel's sojourn in Egypt  |
Birth       | Short: 215 y | Long: 430 y |
------------+--------------+-------------+
Early: when |  Thiele II   |  Thiele IV  |
Terah is 70 |    3899 BC   |   4114 BC   |
------------+--------------+-------------+
Late: when  |   Thiele I   | Thiele III  |
Terah is 130|    3959 BC   |   4174 BC   |
------------+--------------+-------------+

Notably, the NT records that St. Stephen and St. Paul adopted for issues 2 and 3 respectively the options that make up Thiele I chronology:

"Then he [Abraham] left the land of the Chaldeans and settled in Haran. And from there, after his father died, God had him move to this country in which you are now living." (Acts 7:4)

If Abraham departed from Haran - which he did when he was 75 years old (Gen 12:4) - after Terah died - which he did in Haran at the age of 205 years (Gen 11:32) - then Abraham was born when Terah was 205 - 75 = 130 years old.

"Now the promises [of Gen 15:18] were spoken to Abraham and to his seed. He does not say, “And to seeds,” as one would in referring to many, but rather as in referring to one, “And to your seed,” that is, Christ. What I am saying is this: the Law, which came 430 years later, does not invalidate a covenant previously ratified by God, so as to nullify the promise." (Gal 3:16-17)

Assuming that Gen 15:18 was in the same year as Gen 12:3, i.e. when Abraham was 75 years old, then the length of Israel's sojourn in Egypt was:

430 - 130 - 60 - 25 = 215

where:

130 = Jacob's age at entry into Egypt

60 = Isaac's begetting age

25 = time since Gen 15:18 to Isaac's birth when Abraham was 100 years old

Independently from the view of Paul, a 215-year sojourn in Egypt is supported by Ex 6:16-20, which is incompatible with a 430-year stay but lends itself readily to a 215-stay if we assume that Kohath was born just before entering Egypt and that he and his son Amram fathered their respective sons in the middle of their lifetimes, so that: (133 + 137) / 2 + 80 = 215.

Starting from the beginning of construction of the First Temple in the 2nd month of 967 BC, it is easy to reckon that, if the civil year started in Nisan, the dedication of the Temple occurred in the 7th month of 959 BC, i.e. in the 7th month of 3001 AM. This led me to state the hypothesis that the author within the P source of the Pentateuchal text who wrote the chronologies devised them precisely to fix the dedication of the Temple in the year 3001 AM, i.e. at the beginning of the fourth millenium AM, thus echoeing the creation of the sun and the moon on the fourth day to "be for signs, and for seasons, and for days, and years" (Gen 1:14).

I personally hold that Jesus was conceived and born in 8 BC and 7 BC respectively. This implies that, since in the Thiele I chronology AM year + BC year = 3960, He was conceived and born in 3952 AM and 3953 AM respectively. Since Creation was in 1 AM by definition, Jesus was born 3952 years after Creation.

Reference

[1] https://creationwiki.org/Biblical_chronology_dispute

~4ky is probably correct, although various dates have been given, some (according to Wikipedia, which I wouldn't trust as an unbiased source) reaching as far back as ~20ky. Most reputable estimates "top out" at ~6ky, and there are secondary evidences that place a maximum possible age of Earth at ~10ky or less. While precise opinions may vary, a Creation date of ~4000 B.C. to perhaps ~4500 B.C. is generally accepted. (Some may hold to a date of ~5500 B.C., which enjoyed wide consensus prior to the Masoretic Text.)

While it's true Adam lived to be quite old by modern standards, your "back of the envelope" calculation ignores that age at death is very, very different from age of first procreation. Seth, for instance, is attested as being born when Adam is 130. Others earlier in Jesus' lineage are born when their parents are roughly 70-200 years old. (Shem, born to a 502yo Noah, is a notable outlier.) Thus, even a pessimistic estimation based solely on number of generations gives a number of around ~9ky.

However, the Flood reduced the world population to eight humans (and even fewer of many animal kinds). The resulting genetic bottleneck had a severe impact on life expectancy, with lifespans rapidly falling off immediately after the flood before stabilizing again at around 70-100 years, which continues through today. Thus, a couple generations after Noah, we see that the average number of years between each generation in Jesus' lineage drops to around 30 (again with some notable exceptions, such as Abraham). Unsurprisingly, this value also persists to the present day.

Since only about 10-12 generations "waited so long" before producing the children in Jesus' lineage, they contribute about 1500 years, which is the time between Adam and the Flood. The remaining 60 generations, going solely by average time between generations, only give us another 1800 years; we're 700 years short! Of course, this difference is made up by the outliers, which can add hundreds of years each.

This article provides additional details of one particular dating attempt that should help explain where the date comes from.

Addendum:

Various factors (some explained in the previously cited article) affect these date calculations, and subtle interpretations such as what exactly a phrase like "in the fourth year of..." means can add up to a few dozen to perhaps a hundred years in different calculations. Larger discrepancies typically result from disagreements between the Septuagint and other textual sources on the ages of various patriarchs when they begat the sons in Jesus' lineage.

The several much greater numbers mentioned here are poorly substantiated, with the 20ky figure in particular having, as best I can determine, no information available online to back it up. Crawford's (~12ky) supporting material appears to deny the Genesis account and is thus automatically suspect. Another estimate (unclear whether it should be attributed to Camping or McOwen) gives 11ky based on what appear to be highly inflated generational ages; I would consider this estimate highly specious, though perhaps valid if looked at as a "worst case estimate" (that is, a maximum value that can still be Biblically justified, albeit by assuming that the stated generational ages are all unreliable).