Interval · M3 · 4 half steps
The major third
A major third is 4 half steps wide, spanning three letter names: C to E. The bright interval at the bottom of every major chord.
- Half steps4
- Letter names3
- From CC–E
- Inverts tominor sixth
The major third on the staff
An interval’s number counts letter names from the bottom note to the top, both included: C, D and E is three, a third. On the staff, both notes are on lines or both in spaces: from a line, it lands on the next line up; from a space, on the next space up.
The number alone doesn’t make it a major third: major means exactly 4 half steps. Check for sharps and flats, including the key signature: C–E is a major third, but change one note by a half step and the same third on the staff becomes a minor third or something rarer.
Each example below plays the two notes one after the other (a melodic interval), then together (a harmonic interval).
On the piano
Count half steps: every key, black or white, is one half step from the next. From middle C, the major third is the 4th key up, E.
From C, F and G, the white key after next is a major third up (C–E, F–A, G–B). From the other white keys you need a black key on top: D–F♯, E–G♯, A–C♯, B–D♯.
On the white keys alone, the major thirds are C–E, F–A and G–B.
How a major third sounds
A major third sounds bright and settled, open and sweet. It’s the first two notes of a major chord, and it gives major keys their bright colour.
In harmony, it’s an imperfect consonance: sweet and settled, with a colour (major or minor).
Tunes that start with it
- When the Saints Go Marching In starts with a major third up: “Oh when” is C to E.
- Kumbaya begins with a major third up: “Kum-ba-” is C to E.
- The four famous notes of Beethoven’s Fifth Symphony fall a major third: G, G, G, then E♭.
- Swing Low, Sweet Chariot opens with a major third down on “Swing low”.
Hum the tune’s first two notes and you have the interval: a quick way to sing one before you play it.
Where you’ll meet it
A major chord is a major third with a minor third on top (C–E, then E–G). The first, third and fifth notes of a major scale are C, E and G in C major, so the major third is also the space between the 1st and 3rd notes of every major scale. Left-hand accompaniments and two-note right-hand harmonies use it constantly.
Turned upside down, with the bottom note moved up an octave, a major third becomes a minor sixth: 4 and 8 half steps make an octave, and the letter numbers always add up to nine (3 + 6).
To read it fast in real music, practise intervals the way you read words: as shapes. Level 2: right hand skipping thirds in the free sight-reading exercises has plenty of them.
Quiz: the major third
Ten questions: name the interval on the staff, among its neighbours, and play a major third above a written note on the piano below, a MIDI keyboard or your computer keys.
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A major third above every note
| From | A major third up |
|---|---|
| C | E |
| C♯ | E♯ |
| D | F♯ |
| E♭ | G |
| E | G♯ |
| F | A |
| F♯ | A♯ |
| G | B |
| A♭ | C |
| A | C♯ |
| B♭ | D |
| B | D♯ |
Each one is spelt with the 3rd letter up, which is why some need a sharp or flat that looks unusual, like C♯ up to E♯.
Questions
How many half steps are in a major third?
4 half steps, or 2 whole steps. Count every key, black and white, from the bottom note up to the top one: C to E is a major third.
What is a major third above C?
E. It’s spelt with the 3rd letter up from C (C, D and E).
What is the inversion of a major third?
A minor sixth. Move the bottom note up an octave and the four half steps become eight: major third and minor sixth add up to an octave.
How do you recognise a major third on the staff?
Both notes are on lines or both in spaces: from a line, it lands on the next line up; from a space, on the next space up. That tells you the letter distance; then check the sharps, flats and key signature to tell major from minor.
What song starts with a major third?
When the Saints Go Marching In starts with a major third up: “Oh when” is C to E.
Hear every interval in real music
Pianomi, a free sight-reading app for piano, writes new pieces at your level and listens to your MIDI keyboard, so intervals become shapes you read without counting.