When was Jesus killed?
First of all, let's start with when Jesus was born. As clearly proven in the articles “What year was Jesus the Messiah born?” and “What month was Jesus the Messiah born?”, we've learned that He was born in September 3 BC.
As you'll see, the year of His birth, which is the same as that of John the Baptist, will play an important factor in determining the year of His death. So now let's search the Bible for clues that will show us when He got killed.
First Clue: Luke 3:1-3
Luke 3:1 And in the fifteenth year of the government of Tiberius Caesar, Pontius Pilate governing Judea, and Herod ruling as tetrarch of Galilee, and his brother Philip ruling as tetrarch of Iturea and the Trachonitis country, and Lysanias ruling as tetrarch of Abilene,
2 upon the high priesthood of Annas and Caiaphas, the Word of God came on John the son of Zachariah in the desert.
3 And he came into all the regions of the Jordan proclaiming a baptism of repentance for remission of sins,
This first clue will tell us what year John the Baptist started his ministry. Why is this important?
Thirty is the age of spiritual maturity in the scriptures. In Hebraic culture, that would be the qualifying age to become a rabbi or priest. As it says in Numbers 4 verse 3:
Num 4:3 “from thirty years old and above, even to fifty years old, all who enter the service to do the work in the tabernacle of meeting.
Now remember, John was about 6 months older than Jesus. So John would have started his ministry earlier than Jesus.
So now let's go back to Tiberius Caesar. When Augustus died, the Senate named Tiberius emperor on 17 September 14 CE (Interpreters Dictionary of the Bible, Abingdon, 1962, Vol. 3, p. 640).
Luke was using the Hebrew calendar, not the Roman calendar. In 14 CE or AD the start of the Hebraic civil calendar, the month of Tishri, fell sometime in the middle of October of the Roman calendar. So in Luke's reckoning, September of 14 AD was part of the previous Hebraic civil calendar year, and thus counted as the first year of Tiberius' reign.
The second year starts from October or Tishri of 14 AD. Counting forward, the 15th year would be from Tishri (which fell in October) of 27 AD to Tishri of 28 AD.
So John the Baptist would be about 30 years old by March of 28 AD. However, he did not have to be exactly 30 years old to start his ministry especially with his extraordinary spiritual maturity, as the next clue shows.