Tool

The harmonic field of C major

No accidentals in the key signature. Click a degree to hear it, or hear the whole field.

Triads

DegreeSymbolNotesFunction
ICC · E · GTonic
iiDmD · F · ASubdominant
iiiEmE · G · BTonic
IVFF · A · CSubdominant
VGG · B · DDominant
viAmA · C · ETonic
vii°BdimB · D · FDominant

Seventh chords

DegreeSymbolNotesFunction
Imaj7Cmaj7C · E · G · BTonic
ii7Dm7D · F · A · CSubdominant
iii7Em7E · G · B · DTonic
IVmaj7Fmaj7F · A · C · ESubdominant
V7G7G · B · D · FDominant
vi7Am7A · C · E · GTonic
viiø7Bm7♭5B · D · F · ADominant

The notes are spelled in octave 4, from C4. 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.