Throughout the One Piece saga, in nearly every fight that Luffy finds himself, he is usually the shorter opponent.
Conversely, when depicted with other members of the Straw Hat Pirates crew, he seems of average height. This contrast is a bit confusing because, it would mean that most of his opponents, male or female, are giants.
Fortunately, to give some peace of mind, Shueisha, One Piece's publisher has provided an answer for the exact height of Luffy and other One Piece characters, at their Jump Shop in Tokyo's Shibuya District.
One Piece tells the story of Monkey D. Luffy, and his quest to become the greatest pirate of them all. As a child, Luffy mistakenly eats (what appeared to be) the Gum-Gum Devil Fruit which gives him the ability to stretch his body as if it were a rubber band.Read more on screenrant.com