Size Alteration: ability to increase her size from roughly 6'6 to several hundred feet in seconds. This power appears magical in nature, as it violates the square cube law.
Superhuman Strength: Above average in normal form, superhuman when gigantic.
Superhuman Durability: Her durability is higher then an average woman but it is not superhuman (Until she begins growing).
Enhanced Intellect: Giganta is also a brilliant scientist who now retains her full intelligence at any size from normal to maximum.