What is a Tritone?

A tritone is a musical interval that spans three whole tones, which equals six semitones. Because it divides the octave exactly in half, it sits directly between the starting note and the note an octave above. For example, the interval between C and F♯ (or G♭) is a tritone.

The tritone has a very tense and dissonant sound, which historically gave it a mysterious reputation in music theory. In medieval times it was sometimes referred to as diabolus in musica, meaning “the devil in music,” because of the unsettling sound created when the two notes are played together. This tension makes the tritone useful for creating dramatic moments and musical movement.

Despite its dissonant quality, the tritone plays an important role in harmony and chord progressions. It appears in dominant seventh chords and helps create strong resolution toward a tonic chord in many musical styles. Today, tritones are widely used in jazz, classical music, rock, and film scores to add tension, color, and harmonic complexity to compositions.