What is the major third interval?
The major third spans four semitones, creating one of music's most fundamental consonances. From C to E, G to B, or any root up four half-steps, this interval defines the bright, optimistic character that distinguishes major chords from their minor counterparts. Unlike the minor third which sits just one semitone lower, the major third radiates warmth and stability while remaining distinct from the pure resonance of a perfect fifth.
Musicians encounter the major third constantly because it forms the core relationship between scale degrees 1 and 3 in every major scale. Whether you're outlining a simple I chord, building triadic harmony, or improvising melodic phrases, the major third provides the tonal anchor that tells listeners they're hearing something joyful, confident, or resolved.
Music theory fundamentals
In Western harmony, the major third is classified as a major interval because it spans four semitones while containing three letter names (C-D-E, for instance). Combine it with a perfect fifth and you construct the major triad—music's most recognizable chord structure. Stack C, E, and G together and you hear the major third (C to E) working alongside the minor third (E to G) to produce that complete, balanced sonority.
The interval also plays a starring role in major scales and pentatonic scales. Every major scale places a major third between the tonic and mediant (scale degrees 1 and 3), and pentatonic patterns highlight major thirds to reinforce their consonant, singable quality. Because the interval sits comfortably in the overtone series—appearing naturally as the relationship between the fourth and fifth harmonics—our ears perceive it as smooth and consonant even when played melodically or harmonically.
- Semitone distance: four half-steps (0 → 4)
- Scale-degree relationship: tonic to mediant (1 to 3) in major keys
- Harmonic function: defines major chord quality when paired with root and fifth
- Inversion: inverts to a minor sixth (eight semitones)
How the major third sounds
The major third delivers brightness without harshness, openness without emptiness. Train your ear by singing familiar melodies: the opening leap in "Oh When the Saints Go Marching In," the first two notes of "Kumbaya," or the start of the Christmas carol "Have Yourself a Merry Little Christmas." Each example showcases the interval's uplifting, positive character.
When you play a major third harmonically—both notes sounding together—you hear a blend that feels stable yet colorful. It lacks the hollow perfection of a perfect fifth but offers more warmth than the edgier major sixth. Singers and instrumentalists often use the major third to outline major triads in arpeggios, letting the interval's inherent brightness guide listeners toward a sense of resolution and completeness.
Where you'll encounter major thirds
Major thirds appear everywhere in tonal music. Every major chord contains one between its root and third, making the interval indispensable for pop, rock, jazz, and classical harmony. Folk melodies frequently skip up or down by major third to create memorable, singable hooks, while blues and gospel singers bend major thirds toward minor thirds to add expressive nuance.
In jazz and extended harmony, the major third remains crucial even when musicians add sevenths, ninths, or altered extensions. A Cmaj7 chord still relies on that C-E major third to establish its identity, and many jazz voicings stack major and minor thirds in alternating patterns to produce lush, sophisticated colors. Classical composers from Bach to Beethoven used major third relationships to modulate between related keys—moving from C major to E major, for instance, exploits the major third interval on a large-scale harmonic level.
Practice and application
Start by finding every major third on your instrument. On piano, play C to E, D to F♯, E♭ to G, and continue through all twelve keys. Sing each interval ascending and descending, then play them blocked (together) and broken (separately) to internalize the sound. Next, build simple major triads by adding a perfect fifth on top of each major third—C-E becomes C-E-G, D-F♯ becomes D-F♯-A, and so on.
Improvise short melodies using only notes from a C major scale and emphasize leaps by major third (C to E, D to F♯, E to G♯). Notice how these skips convey confidence and brightness compared to stepwise motion or chromatic slides. Finally, practice arpeggios over common chord progressions like I-IV-V-I, focusing on how the major third in each chord anchors the harmony and guides your ear toward resolution.