Tool
The harmonic field of C♯ major 7 sharps in the key signature. Click a degree to hear it, or hear the whole field.
Triads C ♯ I Tonic Diatonic D ♯ m ii Subdominant Diatonic E ♯ m iii Tonic Diatonic F ♯ IV Subdominant Diatonic G ♯ V Dominant Diatonic A ♯ m vi Tonic Diatonic B ♯ dim vii° Dominant Diatonic
Degree Symbol Notes Function I C ♯ C♯ · E♯ · G♯ Tonic ii D ♯ m D♯ · F♯ · A♯ Subdominant iii E ♯ m E♯ · G♯ · B♯ Tonic IV F ♯ F♯ · A♯ · C♯ Subdominant V G ♯ G♯ · B♯ · D♯ Dominant vi A ♯ m A♯ · C♯ · E♯ Tonic vii° B ♯ dim B♯ · D♯ · F♯ Dominant
Seventh chords C ♯ maj7 Imaj7 Tonic Diatonic D ♯ m7 ii7 Subdominant Diatonic E ♯ m7 iii7 Tonic Diatonic F ♯ maj7 IVmaj7 Subdominant Diatonic G ♯ 7 V7 Dominant Diatonic A ♯ m7 vi7 Tonic Diatonic B ♯ m7 ♭5 viiø7 Dominant Diatonic
Degree Symbol Notes Function Imaj7 C ♯ maj7 C♯ · E♯ · G♯ · B♯ Tonic ii7 D ♯ m7 D♯ · F♯ · A♯ · C♯ Subdominant iii7 E ♯ m7 E♯ · G♯ · B♯ · D♯ Tonic IVmaj7 F ♯ maj7 F♯ · A♯ · C♯ · E♯ Subdominant V7 G ♯ 7 G♯ · B♯ · D♯ · F♯ Dominant vi7 A ♯ m7 A♯ · C♯ · E♯ · G♯ Tonic viiø7 B ♯ m7 ♭5 B♯ · D♯ · F♯ · A♯ Dominant
The notes are spelled in octave 4, from C♯4. The function is assigned by degree — tonic on I, III and VI; subdominant on II and IV; dominant on V and VII — which is how the harmonic field is taught. Context can change that reading, and the tool reports the degree.
Related keys A♯ minor Relative: the same key signature, in the other mode. C♯ minor Parallel: the same tonic, in the other mode. C♯ in the dictionary The tonic triad: notes, staff, keyboard and guitar shapes. Read about Diatonic harmony The chords that arise from stacking thirds on each degree of a scale, and why each quality lands where it does. Harmonic function The role each degree plays — tonic, subdominant, or dominant — and the tension that moves one to the next. Roman numeral analysis The notation that describes a chord by the position it occupies in the key rather than by the note it sits on. Minor key harmony The minor harmonic field, which is not one field: the three minor scales produce different chords on the same degree. 
