Minor third
The minor third spans three semitones with a just ratio of 6:5, the darker of the two thirds and the interval that gives minor triads their colour.
From C
- Size
- 3 semitones
- Abbreviation
- m3
- Just ratio
- 6:5 (315.64 cents)
- Equal-tempered
- 300 cents (−15.64 from just)
- Inversion
- Major sixth
What it sounds like
The minor third is an imperfect consonance, the darker of the two thirds. Its just ratio, 6:5, is simple, so the two notes blend and sound settled, though less bright than the major third. Melodically it is a leap with a sad or lyrical colour, and it is common in folk and song melody. Harmonically it is the third of every minor triad, where it sets the minor colour. The notes sound firm rather than harsh, and the interval reads as stable in a chord and expressive in a line.
How to recognise it by ear
The first two notes of 'Greensleeves' rise by a minor third, from A to C. Without that tune, use C up to E♭ in C major, the lower two notes of a minor chord. The sound is darker and more inward than a major third, and a minor chord contains this interval at its base, so a sustained minor chord is a second cue for the same colour. Practice: sing the tonic, sing up a minor third and back, then play the pair to check, and repeat until the darker colour is recognised before the name.
Theory
The minor third inverts to the major sixth: the lower note moves up an octave, the semitones add to twelve, and the quality changes from minor to major. Minor triads contain a minor third from the root followed by a major third; diminished triads contain two minor thirds, and minor seventh chords contain a minor third at the bottom. In the natural minor scale, the third degree lies a minor third above the tonic. Its just ratio, 6:5, measures 315.64 cents. The equal-tempered minor third is 300 cents, so the just size is 15.64 cents wider.
The minor third above every note
Spelled by letter name, so the interval’s number is always right: a minor third above E♭ is not the same spelling as above D♯.
| From | To | Hear it |
|---|---|---|
On the piano
Further reading
- Reading Intervals at Sight: Generic and SpecificFundamentals · 6 min
- Ear Training for Intervals: A Method You Can Practise DailyEar Training & Practice · 7 min
- Just Intonation, Beating and Why Intervals Sound in TuneTuning & Temperament · 8 min
Questions
Why does the minor third sound darker than the major third?
The minor third's upper note sits one semitone lower than the major third's, so it lands on the minor scale's third degree rather than the major one. In a triad, that lowered third is the defining colour of minor. The sound depends on the scale degree as much as on the ratio, so context matters.
Is the minor third a consonance?
Yes, an imperfect consonance. Common-practice harmony classes thirds and sixths as soft consonances, more stable than seconds and sevenths but less stable than the perfect intervals. The minor third is far from dissonant. It works as a stable chord interval, and in counterpoint it is treated as a consonance rather than a tension.
How do I tell a minor third from a major third by ear?
Play the tonic, then sing the top note of each interval. The major third sounds bright and the minor third darker. A quick check is to add the fifth: tonic, minor third and fifth form a minor triad, while tonic, major third and fifth form a major triad. Name the quality only after the sound has been confirmed.