The person helping can either place a flat straight object flat on the head and mark the wall, as before, or simply hold a pencil flat against the top of the person's head and mark the wall directly. Measure the distance from the floor to the spot on the wall to find out the height.
When the series returns as "Naruto: Shippuden," Naruto is aged up to 15. By that point, Naruto is a capable ninja, having defeated his fair share of powerful foes in his early teenage years. Over the course of "Shippuden," Naruto grows from 15 to 17.
When Naruto: Shippuden started, Naruto was 15 years old, when the anime ended, we saw him at 17 years of age. In Boruto: Naruto Next Generations, Naruto Uzumaki should be around 33 years of age.
Considering Boruto is 12 by the Chunin Exams, that means Naruto is at least 31–32. (Accounting for the nine months pregnancy, he's more likely at least 32). If he were 27–28, then that would make him 15–16 when he and Hinata had him.