Tritone: the interval of six half steps
The tritone is an interval of six half steps, exactly half an octave. It is spelled as an augmented fourth or a diminished fifth. It sounds tense and unstable, and it is the key tension inside every dominant seventh chord.
- Half steps6
- Short nameA4 or d5
- From CC to F♯ or G♭
The tritone is the interval that divides the octave exactly in half. It is six half steps wide, which is three whole steps. That is where the name comes from: tri for three and tone for whole step. It is one of the most tense and restless sounds in Western music.
How big is a tritone?
A tritone is six half steps. From C, count up six half steps and you land on F♯ (or G♭). A half step is the distance between neighboring keys on the piano. Six of them make three whole steps, so the tritone is the same as three whole tones in a row, C to D to E to F♯.
The octave has twelve half steps, so the tritone is exactly in the middle. That makes it unique. Its inversion, found by flipping the notes, is also a tritone. F♯ up to C is six half steps too. Every other interval inverts into a different interval, but not this one.
Is it an augmented fourth or a diminished fifth?
The tritone has two names depending on how it is spelled. C up to F♯ spans four letter names (C, D, E, F), so it is a fourth. It is one half step larger than the perfect fourth, so it is an augmented fourth. C up to G♭ spans five letters (C, D, E, F, G), so it is a fifth. It is one half step smaller than the perfect fifth, so it is a diminished fifth.
The two spellings sound identical on the piano, in the same way that F♯ and G♭ are the same key. Which name a composer uses depends on the key and on how the notes are resolved. See enharmonic notes for more on this idea.
Where is the tritone in a major scale?
A major scale contains exactly one tritone between its notes: the distance from the fourth note up to the seventh. In C major, that is F up to B. This pair of notes creates a natural pull that points to the tonic. B wants to rise to C, and F wants to fall to E.
Why is the tritone in the dominant seventh chord?
The dominant seventh chord is built on the fifth note of the scale. In C major, that is G7, made of G, B, D and F. Look at the third (B) and the seventh (F). They are a tritone apart. That one interval is what gives the chord its restless pull.
When G7 resolves to C, the tritone resolves too. B steps up to C, and F steps down to E. The tension turns into the stable third of a C major chord. This resolution is one of the most important moves in tonal music, and it is why the V7 to I change sounds so final.
The same tritone also sits inside the diminished chord, where the root and fifth are a tritone apart, and in the half-diminished chord.
What is the diabolus in musica?
The tritone has an old nickname, diabolus in musica, which is Latin for the devil in music. It is often said that medieval church authorities banned the interval, and that singers could be punished for using it. This story is mostly legend. No evidence supports a formal ban or any punishments.
What is true is that early music theorists considered the tritone unstable, and it was a problem in the system of medieval singing. Writers warned against it in certain melodic and harmonic situations because it did not fit neatly with the perfect intervals of that time. The devil nickname seems to appear much later than the Middle Ages, and the colorful story grew from there.
Where can you hear a tritone?
A famous example is the first two notes of the song Maria from Leonard Bernstein's musical West Side Story. The opening leap is a tritone. Another is the opening riff of Purple Haze by Jimi Hendrix, where a tritone is a main feature of the sound. If you know these tunes, they can help you remember how a tritone sounds.
In blues and rock, the tritone appears as the flattened fifth, sometimes called the blue note. You can read about it on the blues scale page.
| Fact | Value |
|---|---|
| Half steps | 6 |
| Whole steps | 3 |
| Spelled as | Augmented fourth or diminished fifth |
| Example from C | C to F♯ or C to G♭ |
| Inversion | Another tritone |
How can you practice the tritone?
- Play C and F♯ together and listen to the tension.
- Play the notes B and F, then resolve them to C and E. Notice the relief.
- Sing the first two notes of Maria and then find them on the piano.
- Find the tritone in each dominant seventh chord by looking at its third and seventh.
Memory trick: the tritone is three whole tones, halfway through the octave. Both notes in a dominant seventh's tritone lean inward when they resolve.
Tritone from every note
| From | augmented fourth up | diminished fifth up | augmented fourth down |
|---|---|---|---|
| C | F♯ | G♭ | G♭ |
| C♯ | F𝄪 | G | G |
| D♭ | G | A𝄫 | A𝄫 |
| D | G♯ | A♭ | A♭ |
| E♭ | A | B𝄫 | B𝄫 |
| E | A♯ | B♭ | B♭ |
| F | B | C♭ | C♭ |
| F♯ | B♯ | C | C |
| G♭ | C | D𝄫 | D𝄫 |
| G | C♯ | D♭ | D♭ |
| A♭ | D | E𝄫 | E𝄫 |
| A | D♯ | E♭ | E♭ |
| B♭ | E | F♭ | F♭ |
| B | E♯ | F | F |
Check yourself
1. How many half steps are in a tritone?
Answer: 6. A tritone is six half steps, which is three whole steps and half an octave.
2. What are the two names of the tritone?
Answer: Augmented fourth and diminished fifth. One spelling is an augmented fourth, the other a diminished fifth.
3. Which two notes of a G7 chord form the tritone?
Answer: B and F. The third (B) and the seventh (F) of G7 are six half steps apart.
4. Is the story of a medieval ban on the tritone well supported?
Answer: No, it is mostly legend. Early theorists called it unstable, but the ban story is mostly legend.
5. What is the inversion of a tritone?
Answer: Another tritone. Six half steps up and six half steps down both add up to an octave of 12.
Related pages
- Intervals in music: names, sizes and how to count them
- Octave: the interval of twelve half steps
- Diminished chord: what it is and how to build it
- Half-diminished chord: the m7♭5 explained
- Chord progressions: common patterns in every key
- Blues scale: notes, formula and sound
- Enharmonic notes: same sound, different name
- Half steps and whole steps (semitones and tones)
All intervals
See also: intervals explained.