1.What is an Interval? 2.Perfect Intervals 3.Major & Minor Intervals 4.Tritone & Augmented/Diminished 5.Compound Intervals 6.Interval Ear Training
Lesson 1

What is an Interval?

Understand musical intervals - the distance between two notes measured in semitones. Hear every interval with interactive audio examples.

By the end: You can describe an interval as a distance between notes, count its semitones, and name common intervals.

An interval is the distance between two notes, measured in semitones and named by the letter span. It is the basic measurement behind a melody's leaps, a chord's shape, and the space between bass notes.

Every chord, scale, and melody is built from intervals. Knowing the interval lets you describe and recreate the same musical relationship in any key.

Measuring in semitones

You already know the semitone - the smallest step on a piano. Intervals are counted by the number of semitones between two notes. Play the starting note first, then the target note, and listen for the distance between them.

The gap between C and E - count the keys: C#, D, D#, E = 4 semitones

Interval names

Rather than saying "4 semitones", musicians use names. Each interval has a number (how many letter names it spans) and a quality (perfect, major, minor, augmented, or diminished).

All intervals within one octave (from C)

0 C Unison 1:1 Same note
1 C#/Db Minor 2nd 16:15 Tense, close
2 D Major 2nd 9:8 Stepwise, neutral
3 D#/Eb Minor 3rd 6:5 Close, compact
4 E Major 3rd 5:4 Wider, stable
5 F Perfect 4th 4:3 Open, strong
6 F#/Gb Tritone 45:32 Six semitones
7 G Perfect 5th 3:2 Powerful, stable
8 G#/Ab Minor 6th 8:5 Bittersweet
9 A Major 6th 5:3 Warm, sweet
10 A#/Bb Minor 7th 9:5 Bluesy, edgy
11 B Major 7th 15:8 Dreamy, tense
12 C Octave 2:1 Same note, higher

Ratios shown are from just intonation - the pure, mathematically exact tuning. Modern instruments use equal temperament, which slightly adjusts every interval (except the octave) so that all 12 keys sound equally in tune. The difference is tiny but real.

Don't memorise this table all at once. The next few lessons break each group down with sound examples so you can hear the differences.

Melodic vs harmonic intervals

Play two notes one after the other and you hear a melodic interval - this is what melodies are made of. Play them at the same time and you hear a harmonic interval - this is what chords are made of.

Same two notes, same interval name, but the effect is different. In a melody you hear movement; in harmony you hear blend.

Why intervals matter

Intervals are the building blocks of everything:

Chords A major triad = major 3rd + minor 3rd stacked
Scales A major scale = a specific pattern of tones and semitones
Melody The shape of a melody is defined by its interval jumps
Transposing Move every note by the same interval = same song, different key

Try it

Start on C, choose a second key, and count the semitones between them before playing both notes. Try C to E, C to F, and C to G. Write down each interval name, then check the table above.

Repeat the exercise with a different starting note. The note names change, but the same semitone distance keeps the same interval identity.

Key takeaway

An interval is the distance between two notes, counted in semitones. Each interval has a name (like "perfect 5th" or "major 3rd") and a character (bright, dark, tense, stable). Intervals are the DNA of chords, scales, and melodies.

Next: the four special intervals that sound the most stable and clean - the perfect intervals.

Hear intervals in generated music

Generate a melody in Starts and listen to how the intervals between notes create shape and emotion.