Gerrard possesses the vocal range of a contralto but can also reach upward into the dramatic mezzo-soprano range. She has a vocal range from A2 to F♯5 (3 octaves and one note). Her vocal timbre has been described as "rich, deep" which creates a "mournful sound", and her voice is regarded by critics as "simply not of this world". More predominantly, Gerrard's vocal range spans from contralto to dramatic contralto, displayed for examples in "Sanvean", "Sacrifice", "Largo", and "Not Yet"; — to the dramatic mezzo-soprano voice in her other songs, such as "The Host of Seraphim", "Elegy", "Space Weaver", and "Come this Way".