Chord Function
Every chord in a key plays one of three roles: home, movement, or tension. Understanding those roles is the key to understanding why progressions work.
The three chord functions
Each of the seven diatonic chords in a key belongs to one of three functional groups: a tonic chord, a subdominant chord, or a dominant chord.
| Function | Chords | Feeling |
|---|---|---|
| Tonic | I, vi, iii | Stable, at rest, "home" |
| Subdominant | IV, ii | Movement, departure from home |
| Dominant | V, vii° | Tension, wants to resolve |
Why the V chord "dominates"
The V chord contains the scale's leading tone — the note one half-step below the tonic — which creates a powerful pull back home. That built-in tension is why dominant chords drive so much harmonic motion, and why a V-I move (the authentic cadence) is the single strongest way to end a phrase.
Common questions
What are the three chord functions?
Tonic (I, vi, iii — home), subdominant (IV, ii — movement), and dominant (V, vii° — tension that wants to resolve).
What is the typical order of chord function in a progression?
Most move Tonic → Subdominant → Dominant → Tonic, though chords can also move directly from tonic to dominant.
Why is the V chord called dominant?
It contains the leading tone, which pulls strongly back to the tonic — that tension "dominates" the key's harmonic motion.
Can the vi and iii chords substitute for other functions?
Yes — they share notes with I, so they're often used as tonic substitutes for variety while still functioning as "home."
Hear function in real progressions
Melody Monkey visualizes chord progressions on a live guitar, bass, ukulele, or piano — in any key, instantly.
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