While the novel mentions the creature being "gigantic" and "huge," these terms are relative and open to interpretation.
There is no definitive height or weight given, and it's likely Shelley intended to leave the reader to imagine the creature's size based on the descriptions of its actions and the reactions of those who encounter it.
It's important to note that many adaptations of "Frankenstein" have depicted the creature in different ways, sometimes making it significantly taller than a human.