On the last chapter of the manga version, Naruto became the Hokage. How old is he when he became Hokage?
This answer contains spoilers from the end of the manga. Read it at your own risk.
This is just an educated guess, based on information from various point in Naruto's series timeline.
From Naruto's biography:
- In Naruto first season, his age is about 12-13
- In Naruto Shippuden, his age is about 15-17
We also know that he has two children, and his eldest son Bolt (Boruto) is currently a student in the Ninja Academy.
- In Bolt's current character design, Bolt's physical appearance ranges from 10 to 12 years old, probably the same age as his father when Naruto was studying at the Ninja Academy.
- Let's assume 13 is the average age of the students when they graduate from Ninja Academy.
- There is a 2 year time skip in the The Last: Naruto the Movie.
- Let's give 1-3 years margin of error for Naruto and Hinata to have bonded.
- Naruto's current age in Shippuden is about 17.
- Kakashi just stepped down from his position as Hokage. Since he was about 31 in Shippuden, and he became the 6th Hokage after the two year time skip, so he is about 33 at that time.
Solution would be:
a = 10,11,12 = +-2 b = 13 c = 2 d = 1,2,3 = +-2 e = 17 Naruto_Age = a + b + c + d + e Naruto_Age = (+-2) + 13 + 2 + (+-2) + 17 Minima Naruto's Age = 28 Maxima Naruto's Age = 36
Getting the average of minima and maxima, as the two margins of error (which come from Bolt's current age and the time needed for Naruto and Hinata to get together) are pretty much assumed.
Naruto's age when he became Hokage is estimated to be 32.