Intervals: the building blocks of all music
An interval is simply the distance between two notes, measured in semitones — the smallest step on a keyboard or one fret on a guitar. Every melody you can hum and every chord you can strum is a stack of intervals. Learn to hear a dozen of them and written music stops being abstract.
The interval table
- Minor 2nd (1 semitone) — the "Jaws" tension. One fret up.
- Major 2nd (2) — the first two notes of "Happy Birthday".
- Minor 3rd (3) — the sad third; it turns a chord minor.
- Major 3rd (4) — the bright third; it makes a chord major.
- Perfect 4th (5) — "Here Comes the Bride"; the gap between most adjacent guitar strings in standard tuning.
- Tritone (6) — maximum tension, "The Simpsons" theme.
- Perfect 5th (7) — the power-chord interval; the openings of "Star Wars".
- Minor 6th (8) / Major 6th (9) — leaping, romantic ("My Bonnie" for the major 6th).
- Minor 7th (10) / Major 7th (11) — the colour of dominant 7th and maj7 chords.
- Octave (12) — "Somewhere Over the Rainbow"; the same note, higher.
Why intervals matter on your instrument
Guitar strings in standard tuning are a perfect 4th apart (except G→B, a major 3rd) — that is why chord shapes look the way they do. A power chord is just a root, a perfect 5th and an octave. The difference between C major and C minor is a single semitone in the third. Once you see chords as intervals, moving them around the neck or to a ukulele becomes mechanical.
Train your ear, not just your fingers
Reading about intervals is like reading about swimming. Ten minutes a day in our free ear training drills — start at level 1 with just fourths, fifths and octaves — and within a couple of weeks you will name intervals in songs on the radio. Tuning by ear also gets easier: when you tune with reference tones, you are matching a unison, the simplest interval of all.