Minor 3rd

General info

Interval

Minor 3rd

Quality

Minor

Semitones

3

Degree distance

3 degrees

Degree

b3

Interval structure

Lower note

A# (466.2 Hz)

Lower note role

Root

Upper note

C# (554.4 Hz)

Upper note role

Minor third (b3)

Degree formula

I

bIII

Semitone formula

3 semitones (1.5 tones)

Interval construction

Interval formula

m3

Brief explanation

A minor third spans three semitones. Above a root, it defines the minor quality of a triad but does not determine a specific mood by itself.

Interval notes

Consonance / dissonance

Sonority

Imperfect consonance

Explanation

A minor third is an imperfect consonance. In tertian harmony, it serves as a stable structural interval in minor and diminished chords.

How the interval sounds

Tendencies & resolutions

The minor 3rd is a stable consonance and does not require mandatory resolution. In a chord context, it defines the minor quality and can remain in place. In melody, a minor 3rd often resolves by stepwise motion to a 2nd or 4th.

Harmonic context

The minor 3rd is the interval between the first and third degrees of a minor triad. It appears in min, m7, dim, dim7, and m7b5 chords. In minor-leaning scales (Aeolian, Dorian, Phrygian), the minor 3rd forms the sonic foundation. A diminished triad consists of two stacked minor 3rds.

Interval inversion

Inverts to

Major 6thM6

Quality change

Minor

major

Inversion rule

When inverting a minor 3rd, the lower note moves up an octave. 3 semitones (m3) become 9 semitones — a major 6th (M6).

Related intervals