What is the most accurate calculation of Jesus' birth date?

Speculation abounds regarding the year and the month in which Jesus was born. Although most views range from 6 to 4 B.C., there are some suggestions that he could have been born in 7 or even 8 B.C. The Bible provides only a few clues.

Luke’s gospel sets the scene by saying that after Mary was visited by the angel Gabriel, Mary went to see her cousin Elizabeth who was six months pregnant (Luke 1:36). Mary stayed with Elizabeth for about three months before she returned home (Luke 1:56). Below is a comment from the NIV Bible regarding Matthew 3:1:

John the Baptist, the forerunner of Jesus, born circa 7 B.C. to Zechariah (a priest) and Elizabeth (cousin to Mary).

It is worth remembering that in Judaism the age of a child is counted from its conception, not its birth. If Jesus was conceived during Chanukkah – Festival of Lights (December, when Elizabeth was 6 months pregnant), he would have been born during the Festival of Sukkot (end September or beginning October) 7 B.C.

Luke’s gospel says that Jesus’ birth happened during the time when Quirinius was governor of Syria. “In those days Caesar Augustus issued a decree that a census should be taken of the entire Roman world. (This was the first census that took place while Quirinius was governor of Syria)” (Luke 2:1–2). This is problematic because history suggests Quirinius was governor between A.D. 6 and 7, about 10 years after the birth of Jesus. Here is one explanation:

The Greek word for “first” in Luke 2:2 is a form of the word protos and can be translated “before.” Thus Luke 2:2 could actually be translated, “This was the census taken before Quirinius was governor of Syria.” Quirinius actually ruled Syria on two separate occasions, and there were actually two censuses taken. The “first census” mentioned in Luke 2:2 occurred during Quirinius’ first term as governor, and another during his second term. The second census is mentioned in Acts 5:37 and probably took place between A.D .6 and 7 (Josephus links this census to an uprising led by Judas of Galilee). Luke was the author of both the Gospel of Luke and the book of Acts, and his goal was to write “an orderly account” (Luke 1:3). It seems that Luke did write a careful, orderly account: he mentions two censuses, and it was during the first one that Jesus was born. It would be unlikely for such a meticulous historian to make a blatant mistake in his timeline of events. Source: https://www.gotquestions.org/Quirinius-census.html

With regard to the census mentioned in Luke 2:1-2, 5th century historian Orosius records that Augustus “ordered a census of each province everywhere and all men to be enrolled.” Josephus notes that, "When all the people of the Jews gave assurance of their goodwill to Caesar, and to the king's government, these very men [the Pharisees] did not swear, being about six thousand." This first census took place before the death of Herod the Great in 4 B.C. There was also a census in 8 B.C. but for Roman citizens only.

Another school of thought gives the following dates:

The conception of John 23rd Sivan = June 23-24, 5 B.C. The birth of John 7th Nisan = March 28-29, 4 B.C. The Miraculous "Begetting" 1 Tebeth = December 25, 5 B.C. The Nativity 15th Tisri = September 29, 4 B.C. It thus appears without the shadow of a doubt that the day assigned the the Birth of the Lord, viz. December 25, was the day on which He was "begotten of the Holy Spirit", i.e. by pneuma hagion = divine power (Matt. 1:18, 20 marg.), and His birth took place on the 15th of Ethanim, September 29, in the year following, thus making beautifully clear the meaning of John 1:14, "The Word became flesh" (Matt. 1:18, 20) on the 1st Tebeth or December 25 (5 B.C.), "and tabernacled (Gr. eskeno-sen) with us", on 15th of Ethanim or September 29 (4 B.C.). Source: https://www.levendwater.org/companion/append179.html#abia

To sum up:

Jesus began His ministry during the time John the Baptist ministered in the wilderness, and John’s ministry started “in the fifteenth year of the reign of Tiberius Caesar, Pontius Pilate being governor of Judea, and Herod being tetrarch of Galilee, and his brother Philip tetrarch of the region of Ituraea and Trachonitis, and Lysanias tetrarch of Abilene, during the high priesthood of Annas and Caiaphas” (Luke 3:1-2). The only time period that fits all of these facts is A.D. 27-29. If Jesus was “about thirty years of age” by A.D. 27, a birth sometime between 6 and 4 B.C. would fit the chronology. More specifically, Jesus would have been approximately 32 years old at the time He began His ministry (still “about thirty years of age”). https://www.gotquestions.org/what-year-was-Jesus-born.html

Another useful source of information is this article by John Mosley on errors regarding the year in which Jesus was born: https://www.ips-planetarium.org/page/a_mosley1981 Section 3 discusses the Old Roman calendar which was based on the founding of Rome (AUC) but fell into disuse. Section 6 explains how the census was not for taxation purposes but to give an oath of allegiance, and this may have happened in 3 B.C.

Although there is quite some space for speculation. I would like to highlight the perspective presented in the Literature of Jehovah's Witnesses, wich regularly mentions the Birth of Jesus to have likely taken place in fall of 2 BCE.

The Bible historian Luke tells us that John came baptizing in the 15th year of Tiberius Caesar. (Lu 3:1-3) Augustus died on August 17, 14 C.E. On September 15, Tiberius was named emperor by the Roman Senate. The Romans did not use the accession-year system; consequently, the 15th year would run from the latter part of 28 C.E. to the latter part of 29 C.E. John was six months older than Jesus and began his ministry (evidently in the spring of the year) ahead of Jesus as Jesus’ forerunner, preparing the way. (Lu 1:35, 36) Jesus, whom the Bible indicates was born in the fall of the year, was about 30 years old when he came to John to be baptized. (Lu 3:21-23) Therefore he was baptized, most likely, in the fall, about October of 29 C.E. Counting back 30 years would bring us to the fall of 2 B.C.E. as the time of the human birth of the Son of God. [Insight on the scriptures Volume 1 page 1094-1095]

Although, it might look a bit weird that the birthday of jesus is estimated to be in the year 2 B.C.E. More information about that can be found here Watchower 1968 8/15 p. 504 pagragraph 13, 14. Another more recent source article from Jehovahs Witneses on the subject can be found in The watchtower 1999 11/1 page 4-5.

The reason you are not finding accurate dates for the events of Jesus' birth, ministry and death is that nobody knows.

As you have seen, there are estimates, but the figures you quote are as accurate as it gets. The gospel writers did not see fit to tell us exact dates, presumably because they did not consider it important.

You can of course find people who claim to have worked out the exact dates, but they are not widely accepted.

The Exact Day is Unknown

The exact date of Jesus' birth is not given. This is very likely because, if we knew it, we would reverence the day, rather than the Man. However, we can come to within about thirty days or so of it, and we know for certain that Jesus was not born on Christmas.

Narrowing the Range

First, a list of some of the guiding concepts that can help us to pinpoint, and narrow, the actual range of time (some of this for the month and some for the year):

1. The timing of Mary's pregnancy compared with that of her cousin Elisabeth

2. The timing of Zachariah's priestly duties, as these followed a regular and long-established schedule

3. The prophecies of Daniel 9 which foretold the 7-year period during which the Messiah would minister, being "cut off" in the midst of that time (after just 3.5 years of it)

4. The timing of Passover when Christ was crucified

Because a full exposition of each of these points would be lengthy, I will give some of the dates and times, and scriptures which must be studied to understand those times, so that the reader who is unsatisfied with the calculations can undertake to calculate them personally--and learn more in the process.

The Pregnancies

Mary conceived, and went to visit Elisabeth, her cousin, whom she had heard was also pregnant in her old age.

²⁴ And after those days his wife Elisabeth conceived, and hid herself five months, saying, ²⁵ Thus hath the Lord dealt with me in the days wherein he looked on me, to take away my reproach among men. ²⁶ And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth, ²⁷ To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary. (Luke 1:24-27, KJV)

³⁶ And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. ³⁷ For with God nothing shall be impossible. ³⁸ And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her. ³⁹ And Mary arose in those days, and went into the hill country with haste, into a city of Juda; ⁴⁰ And entered into the house of Zacharias, and saluted Elisabeth. (Luke 1:36-40, KJV)

Mary's pregnancy is plainly spelled out to be six months' behind that of Elisabeth, placing John the Baptist six months older than Jesus, being born six months ahead of Jesus.

Zacharias' Course of Service in the Temple

Every priest coveted the opportunity to minister in the temple. To bring order and fairness to the system, David was the first divide the priests and Levites up by courses to serve on a regular schedule. Later kings confirmed and continued this program of service.

³ Now the Levites were numbered from the age of thirty years and upward: and their number by their polls, man by man, was thirty and eight thousand. ⁴ Of which, twenty and four thousand were to set forward the work of the house of the LORD; and six thousand were officers and judges: ⁵ Moreover four thousand were porters; and four thousand praised the LORD with the instruments which I made, said David, to praise therewith. ⁶ And David divided them into courses among the sons of Levi, namely, Gershon, Kohath, and Merari. (1 Chronicles 23:3-6, KJV)

The instructions which follow in the next chapter (1 Chr. 24) show the courses to have been laid out like this:

(NOTE: Parenthesized names in the table are not explicitly given in the Hebrew.)

Zacharias is said to be of that eighth (8th) course: "Abijah" (Hebrew) / "Abia" (Greek).

There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth. (Luke 1:5, KJV)

With 24 courses, this means there can be two courses per month. This would mean Zacharias would serve in the fourth month. The first month was defined as the start of the Jewish year. It was the month of Passover.

In the fourteenth day of the first month at even is the LORD's passover. (Leviticus 23:5, KJV)

The Passover usually came around the end of March or the beginning of April by our modern calendars--it was spring time. Assuming roughly mid-April for the Passover, and the first of the month being two weeks earlier, the eighth course, that of "Abia," should be expected to fall around the latter half of July (from mid-month to its end). It would have been after this that Zacharias returned home, and if conception happened shortly thereafter, John could be expected roughly nine months later, around April of the following year. This would time Jesus' life and ministry perfectly, as he is to be born six months later, and it was at Passover time, 3.5 years into his ministry, that he is crucified (aged 33.5, because his ministry is said to begin when he is thirty and is baptized by John).

Which brings us to the 70-weeks' prophecy of Daniel 9.

The Seventy Weeks / 490 Years

The prophecy is given in Daniel 9 as follows.

²⁴ Seventy weeks are determined upon thy people and upon thy holy city, to finish the transgression, and to make an end of sins, and to make reconciliation for iniquity, and to bring in everlasting righteousness, and to seal up the vision and prophecy, and to anoint the most Holy. ²⁵ Know therefore and understand, that from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times. ²⁶ And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined. ²⁷ And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate. (Daniel 9:24-27, KJV)

Using the prophetic principle of a day representing a year (a natural understanding for Hebrew speakers since the word "yowm" in Hebrew can mean day, time, or year) as found in Ezekiel 4:6 and Numbers 14:34, the 490-day period is found to span 490 years, and this begins with the decree to restore and rebuild Jerusalem. This decree is established in history as having been proclaimed in 457 B.C. The first "seven weeks" of this prophecy, representing 49 years, indicate the time during which Solomon's temple was to be rebuilt. Owing to political problems, work had stopped for about three years, but the Jews give us the correct figure of how many years the building had actually occupied.

Then said the Jews, Forty and six years was this temple in building, and wilt thou rear it up in three days? (John 2:20, KJV)

So the temple was built during that first seven-week (49-year) period of the prophecy. The last week (seven years) of the prophecy is split in the middle by Jesus' death; the first part being the period of his earthly ministry, and the last half being the final years of probation for the Jewish nation before God turns from them to the Gentiles at the stoning of Stephen.

To arrive at the year of Jesus' birth requires simple subtraction (working backwards) from the end of the prophetic period and/or from the time of the crucifixion.

The 490-Year Period in Reverse-Chronological Summary

A.D. 34 -- stoning of Stephen / end of the 490 years
A.D. 30/31 -- Jesus is crucified, causing the sacrificial system to cease
A.D. 27 -- Jesus is baptized at age 30 (see Luke 3:23)
4 B.C. -- Jesus is born (remember, there is no zero year between the B.C. and A.D. dates)
457 B.C. -- the start of the 490 years, and the start of the rebuilding of the temple in Jerusalem

The Timing of Passover in Year of Crucifixion

The Passover lamb, whose type Jesus must fulfill, was always eaten on the day of Passover, at the start of that day, which biblically is evening, following sunset. The Passover was considered a sabbath, even when it did not land on the seventh day of the week; and sabbaths were always observed from sundown to sundown. In A.D. 30, Passover came on a Friday. Thursday evening, at the start of Passover, the passover lamb was eaten in the upper room by the disciples. Thursday night found them in the Garden of Gethsemane, where Jesus began to bear the sins of the world, placed on him as the Lamb of prophecy. He was arrested, taken to Pilate, then to Herod, then back to Pilate before being sentenced to crucifixion well into the morning on Friday (Passover), and Jesus himself was sacrificed and died on this same day. He rested in the tomb on the Sabbath, the day following, and was resurrected on the first day of the week (Sunday morning).

Some Finer Details

Shepherds did not stay outdoors through the night with their sheep during the winter months. That was the rainy season, and would have been the time when crops would be growing in the fields. The earliest rains might begin in September or October, and by November, the fields would have been under agriculture again, having lain fallow during the dry months of summer from about May/June through September/October. See HERE for some details.

This eliminates the winter months, beginning around November and continuing through at least April/May, as a time when shepherds would have been out keeping watch over their flocks by night; and the shepherds were on duty when Jesus was born (see Luke 2:8).

Why 30/31 AD?

The calendar reckoning we use today does not match the reckoning used in Jesus' time among the Jews. As God had established, they observed the first month of the year (Nisan/Abib) in about April, celebrating Passover in the midst of that month. Because we, today, start the year on January 1, this leaves some ambiguity as to which "year" is being addressed. Many such dates are denoted, therefore, as a range, as in this case "30/31." It would be A.D. 30 as of January 1, but the Jews would have considered it A.D. 31 when Jesus was crucified, on Passover, two weeks into their New Year.

In fact, from about April onward for each and every year discussed here, the problem is the same--which is one source of confusion to many people.

Conclusion

By far the strongest evidence in favor of a September/October birth is found in a study of the priestly courses and following the timing of Zacharias' course, the birth of John the Baptist, and the birth of Jesus six months later. Zacharias would have served in July, and assuming Elizabeth was pregnant in August, John would have been born in April, leading to Jesus' birth in about September/October, six months later. Naturally, these calculations assume that the period of gestation was essentially the same in the days of Christ as it would be now (about 36-40 weeks; nominally 9 months).

Given a late September/early October date for Jesus' birth, all other prophecies relative to the time of the Messiah and Christ's ministry are well aligned. It is virtually certain, therefore, that Jesus was born in the early to mid-autumn of 4 B.C.