Galactus' height varies significantly depending on the context. In Marvel Comics, his official height is about 28 feet 9 inches (nearly 30 feet). However, due to his cosmic nature, Galactus can manipulate his size and appear much larger or smaller as needed. In the 2025 movie "The Fantastic Four: First Steps," Galactus is depicted at an enormous scale. Early trailers show him casting a shadow over Manhattan that suggests he could be around 12 miles (19 km) tall or more. In other scenes, he shrinks to city-sized or skyscraper- sized, with heights ranging roughly from 1,000 feet (about 300 meters) to about 1,400 feet (approximately 430 meters), which is still colossal compared to human-sized characters or city buildings. These massive size shifts illustrate that Galactus can change from planet-sized to smaller scales to interact with the environment and characters.

So, while the comic book "standard" is around 29 feet tall, the cinematic depiction shows him as potentially miles tall but also able to shrink to roughly skyscraper height depending on the situation.