Jesus lived 33 1/2 years. We know this, as he began his ministry about 30 years of age (Luke 3:23). The length of his ministry was 3 1/2 years, which can be shown from the prophecy in Daniel.

In Daniel 9, God tells Daniel that Messiah (Jesus) would come (begin his ministry) after 69 weeks of years (69×7=483 years). In the middle of the week (half of 7 is 3 1/2 years) he would put a stop to sacrifice and offering (Jesus' sacrifice for the sin of mankind would be complete – he would die on the cross).

Dan 9:25 "So you are to know and discern that from the issuing of a decree to restore and rebuild Jerusalem until Messiah the Prince there will be seven weeks and sixty-two weeks (7+62=69); it will be built again, with plaza and moat, even in times of distress… And he will make a firm covenant with the many for one week (at the beginning of the 70th. week), but in the middle of the week (69 1/2 weeks) he will put a stop to sacrifice (Jesus was crucified Friday April 3, 33 AD, and since the Jewish New Year begins in September, 6 months earlier,  this is the half-year required so that he would be cut-off in the midst of the week)…”

Further supporting this, is the fact that the Gospel of John records three Passovers during Jesus' ministry (John 2:13-25 after his ministry began, John 6:4, and John 11:55 begins the passage of the last Passover when Jesus was crucified). The Passover was celebrated once a year, so that would be three years, plus the time after his baptism before the first Passover, which we deduce from the prophecy in Daniel 9 (mentioned above) to be another 6 months. Add this to the 30 years when he began his ministry and we see that he lived 33 1/2 years (3 1/2 + 30 = 33 1/2).