How old was Jesus when he died on the cross?

No one knows exactly how old Jesus was when he died on the cross, but he was probably 33 years of age.  This is drawn from two main things.  First, Jesus was baptized to enter into the Melchizedek priesthood.  In Matthew 3:13-15 it says, "Then Jesus came from Galilee to the Jordan to be baptized by John. But John tried to deter him, saying, "I need to be baptized by you, and do you come to me?' Jesus replied, 'Let it be so now; it is proper for us to do this to fulfill all righteousness.'"  Jesus got baptized to fulfill all righteousness.  This fulfillment was in reference to the Old Testament requirements for being a priest, which among them was being the minimum age of 30.  "from thirty years and upward, even to fifty years old, all who enter the service to do the work in the tent of meeting," (Num. 4:3).  This is fulfilled in the Scriptures at Luke 3:21-23, "Now it came about when all the people were baptized, that Jesus also was baptized, and while He was praying, heaven was opened, 22 and the Holy Spirit descended upon Him in bodily form like a dove, and a voice came out of heaven, “Thou art My beloved Son, in Thee I am well-pleased.” 23 And when He began His ministry, Jesus Himself was about thirty years of age, being supposedly the son of Joseph, the son of Eli..."

Second, most Christian scholars agree that Jesus' ministry lasted 3 1/2 years.  So, 30+ 3 1/2 equals the age of 33.