Intervals

An interval is the distance between two notes, measured in semitones. The smallest is 1 semitone (one fret, one piano key); 12 semitones make an octave.

The harmonic series determines which intervals sound consonant or dissonant, and so what role each one plays.

Within one octave:

• 0: unison
• 1: minor 2nd
• 2: major 2nd
• 3: minor 3rd
• 4: major 3rd
• 5: perfect 4th
• 6: tritone
• 7: perfect 5th
• 8: minor 6th
• 9: major 6th
• 10: minor 7th
• 11: major 7th
• 12: octave