Tritone

General info

Interval

Tritone

Quality

Tritone

Semitones

6

Degree distance

3 whole tones (exactly half an octave)

Degree

b5

Interval structure

Lower note

E (329.6 Hz)

Lower note role

Root

Upper note

Bb (466.2 Hz)

Upper note role

Tritone (#4 / b5)

Degree formula

I

#IV / bV

Semitone formula

6 semitones (3 whole tones)

Interval construction

Interval formula

TT (A4 / d5)

Brief explanation

A tritone spans six semitones and divides the octave in half. Depending on diatonic spelling, it is an augmented fourth (#4) or diminished fifth (b5).

Interval notes

Consonance / dissonance

Sonority

Sharp dissonance

Explanation

A tritone is classified as a dissonance. On inversion, an augmented fourth becomes a diminished fifth and vice versa; the acoustic span remains six semitones.

How the interval sounds

Tendencies & resolutions

Resolution depends on spelling and function. In G7, B rises to C while F falls to E, so the tritone expands to a sixth. A leading-tone diminished chord permits other inward or outward voice-leading patterns.

Harmonic context

The tritone between the 3rd and 7th of a dominant seventh chord directs its voice leading toward tonic. It also appears in diminished and half-diminished chords; b5 is a blue note in the blues scale, and the interval underlies tritone substitution in jazz.

Interval inversion

Inverts to

TritoneTT

Quality change

Tritone

tritone (inverts to itself)

Inversion rule

The tritone is the only interval that inverts to itself. 6 semitones remain 6 semitones. An augmented 4th inverts to a diminished 5th and vice versa.

Related intervals