Now that Big Mom’s in-story power for changing her size has been added to the anime, her prior size changes in the show make no logical sense.
The only thing that’s consistent about Big Mom’s height in the One Piece anime is how inconsistent it is. For instance, in some shots, she looks almost twice as tall as Jimbei, but other shots have him barely come up to her kneecaps. There’s a purpose behind this, but it’s still confusing.
There are now two official reasons for Big Mom’s size changes. One is the artistic reason used by Toei Animation. The other is the in-story power provided by Oda, which was recently added to the anime. These two reasonings for Big Mom’s size conflict with each other and make the whole situation a convoluted mess.
How Big Is Big Mom Supposed to Be?
Canonically, Big Mom is 880cm, almost 29 feet tall. This technically means that when she’s shown to be bigger than usual, she’s actually being shown closer to her real size. The rest of the time, she’s drawn smaller so that her face and body can fit in the necessary shots. Even so, there are still instances where she’s drawn much bigger than she’s supposed to be.
Initially, Big Mom’s size changes were a simple artistic choice by Toei Animation. They were meant to make her come off as a more powerful and imposing figure. The studio has been using this technique as far back as with Fist of the North Star — possibly even earlier than that.
In Big Mom’s case, she’s generally drawn to be the biggest person in the room by far. The only exception to this has been when she’s shown next to Kaido. This is likely because they’re meant to be similarly imposing figures in the One Piece world. That said, since the King of the Beasts is only 24 and-a-half feet tall, Big Mom technically dwarfs him, too. In any case, as long as her size change wasn’t addressed directly by the narrative, this creative liberty could be accepted.
This point changed significantly when Big Mom ended up being given a canonical power that would change her size. In Chapter 1031, “Warrior of Science,” she traded a year of her lifespan to increase her size and strength during her battle with Eustass Kid and Trafalgar Law. This scene became canon to the anime in Episode 1056, “A Countercharge! Law and Kid’s Return-Attack Combination.”
Now that Big Mom has a confirmed, canonical ability to change her size, all those size changes that don’t rely on this method seem illogical. Unless she’s giving up a year of her life every time she wants to look menacing, which is unlikely, her height ought to remain consistent. Where Toei Animation once took artistic liberty, they are now obligated to provide a logical, in-story explanation.
