Pitch & Intervals

Minor Third

Written as m3

Definition

A minor third (m3) is an interval of three half steps spanning three letter names, such as A–C, D–F or C–E♭. It is the bottom interval of a minor chord and sounds darker than a major third.

A minor third spans three letter names and three half steps: A up to C, D up to F, E up to G, C up to E♭. Abbreviated m3, it measures 300 cents in equal temperament.

Three one-bar examples of three half notes each: the lower note, the upper note, then both together. A4 and C5, D4 and F4 in treble clef; C3 and E flat 3 in bass clef. — Three minor thirds, each shown in one bar: the lower note, the upper note, then both together. A–C and D–F in the treble clef, C–E♭ in the bass clef.

Counting it

Count the letters, including both ends: A–B–C is three, so A–C is a 3rd. Then count half steps from A: A♯ (1), B (2), C (3). Three half steps make it minor; four would make it a major third. On the staff, a 3rd goes from a line to the next line, or from a space to the next space.

D to F: count D♯ (1), E (2), F (3). A to C: count A♯ (1), B (2), C (3). Three half steps make a minor third.

Among the white keys, four of the seven 3rds are minor: D–F, E–G, A–C and B–D. The other three, C–E, F–A and G–B, are major. To turn a major third into a minor one, flatten the top note (C–E♭) or sharpen the bottom note (C♯–E).

Minor thirds in chords

A minor triad is a minor third with a major third stacked on top: A–C–E. A major triad reverses the order, major third first (C–E–G). A diminished triad stacks two minor thirds (B–D–F), and a diminished seventh chord stacks three, dividing the octave into four equal parts.

The minor third is also the distance between a major key and its relative minor: C major and A minor share a key signature, and A lies a minor third below C.

How it sounds

A rising minor third opens the folk song "Greensleeves". A falling minor third, from sol down to mi in solfège, is one of the first intervals children sing, and many playground chants are built on it. Harmonically, the minor third is a consonance (an imperfect consonance in classical theory), and it gives minor chords their darker color.

Inversion and look-alikes

Inverted, a minor third becomes a major sixth: A–C becomes C–A, and 3 + 9 = 12. The same two keys spelled with neighboring letters, such as C–D♯, form an augmented second. It sounds identical on a piano, and it appears in the harmonic minor scale between the 6th and 7th notes (F–G♯ in A harmonic minor).

Practice with Major & minor 2nds and 3rds and Name the intervals: major or minor.

Common questions

How many half steps are in a minor third?

Three. From A: A♯ (1), B (2), C (3). A major third has four.

Why does a minor third sound sad?

It doesn't always. In Western music the minor third above the root is what makes a chord minor, and listeners who grew up with that music often hear minor chords as darker or sadder. Tempo, rhythm and context matter just as much: plenty of lively dance music is in a minor key.