Tool
The harmonic field of B major 5 sharps in the key signature. Click a degree to hear it, or hear the whole field.
Triads B I Tonic Diatonic C ♯ m ii Subdominant Diatonic D ♯ m iii Tonic Diatonic E IV Subdominant Diatonic F ♯ V Dominant Diatonic G ♯ m vi Tonic Diatonic A ♯ dim vii° Dominant Diatonic
Degree Symbol Notes Function I B B · D♯ · F♯ Tonic ii C ♯ m C♯ · E · G♯ Subdominant iii D ♯ m D♯ · F♯ · A♯ Tonic IV E E · G♯ · B Subdominant V F ♯ F♯ · A♯ · C♯ Dominant vi G ♯ m G♯ · B · D♯ Tonic vii° A ♯ dim A♯ · C♯ · E Dominant
Seventh chords B maj7 Imaj7 Tonic Diatonic C ♯ m7 ii7 Subdominant Diatonic D ♯ m7 iii7 Tonic Diatonic E maj7 IVmaj7 Subdominant Diatonic F ♯ 7 V7 Dominant Diatonic G ♯ m7 vi7 Tonic Diatonic A ♯ m7 ♭5 viiø7 Dominant Diatonic
Degree Symbol Notes Function Imaj7 B maj7 B · D♯ · F♯ · A♯ Tonic ii7 C ♯ m7 C♯ · E · G♯ · B Subdominant iii7 D ♯ m7 D♯ · F♯ · A♯ · C♯ Tonic IVmaj7 E maj7 E · G♯ · B · D♯ Subdominant V7 F ♯ 7 F♯ · A♯ · C♯ · E Dominant vi7 G ♯ m7 G♯ · B · D♯ · F♯ Tonic viiø7 A ♯ m7 ♭5 A♯ · C♯ · E · G♯ Dominant
The notes are spelled in octave 4, from B4. 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 G♯ minor Relative: the same key signature, in the other mode. B minor Parallel: the same tonic, in the other mode. B 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. 
