While the Bible does not give us a detailed timeline of David’s life, it does provide enough information to know or approximate how old David was at significant moments in his life.
How old was David when Samuel anointed him king?
The Lord had instructed Samuel the prophet to go to the house of Jesse in Bethlehem to anoint Israel’s next king. As the youngest boy in Jesse’s family, David was regarded as irrelevant. His father did not even bother to call him to meet Samuel. But when Samuel considered Jesse’s seven older sons, God rejected them all. The prophet asked if Jesse had any other sons, and then David, who was out tending sheep, was called and Samuel anointed him. As is often the case, God chose the least likely candidate (1 Samuel 16:1–13). We are not told precisely how old David was at this time, but we know he was just a boy, probably between 10–15 years of age.
How old was David when he fought Goliath?
Scripture gives us stronger clues regarding David’s age when he fought Goliath. While the Philistines were at war with Saul, their giant, Goliath, taunted the armies of Israel daily. But none of the Hebrew soldiers had the courage to face Goliath one on one.
At this time, David’s three oldest brothers were serving on the battle lines. David was sent to them by his father to deliver provisions. When David heard the defiant words of Goliath, he was grievously offended and told King Saul he would stand up and fight against Goliath. “Don’t be ridiculous!” was Saul’s reply. “There’s no way you can fight this Philistine and possibly win! You’re only a boy, and he’s been a man of war since his youth” (1 Samuel 17:33, NLT).
The term Saul used here to describe David’s age means “adolescent.” David was most likely still a teenager, probably 16–19 years old. The fact that David was not yet serving in the army tells us he was definitely under 20 (see Numbers 1:3).
Likewise, since Scripture says that David’s three oldest brothers were in the army (1 Samuel 17:13), we know they were 20 years or older. That leaves four brothers between them and David, strengthening the notion that David was a teenager when he fought Goliath.
How old was David when he became king?
The Bible is forthright in revealing, “David was thirty years old when he became king, and he reigned forty years” (2 Samuel 5:4). Thus, David took the throne of Israel at about the same age that Jesus would begin His earthly ministry (Luke 3:23).
How old was David when he died?
Since we know that David was 30 years old when he became king, and he reigned for a period of 40 years, that places him around 70–71 years old when he died (1 Kings 2:10). When the end came, David “died at a good old age, having enjoyed long life, wealth and honor” (1 Chronicles 29:28).