Tritone (augmented fourth / diminished fifth)
A tritone is 6 half steps, written A4. From C it reaches F♯. Hear it one note after the other, then together.
What it sounds like
Six half steps, exactly half an octave. It sounds restless and unresolved, which is why it was once nicknamed "the devil in music".
Every dominant seventh chord contains one, between its 3rd and 7th, and that tension is what pulls V7 to I. It is also the ♭5 of the blues scale.
How to recognise a tritone by ear
There is no scale step that lands on it cleanly, which is part of its strangeness: sing fa to ti in a major scale. It sits exactly halfway to the octave and never sounds finished; your ear wants it to move out by a half step each way.
Inside the C major scale, the tritone is F–B, the only one in the key. Being rare in the scale is part of why it stands out.
Add an octave and a tritone becomes an augmented eleventh (18 half steps), the ♯11 of the Lydian sound. Intervals bigger than an octave are called compound intervals; they keep the character of the smaller interval but sound more open.
Chords with a tritone above the root (spelled as a ♭5 or ♯11), shown on C: Cdim, Cdim7, Cm7♭5.
A tritone from every note
The letter name moves up 3 letters (a "fourth") and the distance is always 6 half steps. The tritone has two spellings: as an augmented fourth (up four letters) or a diminished fifth (up five).
| From | Up a tritone | As a diminished fifth | |
|---|---|---|---|
| C | F♯ | G♭ | |
| D♭ | G | A𝄫 | |
| D | G♯ | A♭ | |
| E♭ | A | B𝄫 | |
| E | A♯ | B♭ | |
| F | B | C♭ | |
| F♯ | B♯ | C | |
| G | C♯ | D♭ | |
| A♭ | D | E𝄫 | |
| A | D♯ | E♭ | |
| B♭ | E | F♭ | |
| B | E♯ | F |
Finding it on guitar
On one string, a tritone is 6 frets up. Across to the next higher string it's 1 fret up (the strings are a perfect fourth apart, except G to B, where you add one fret). The diagram starts from A on the low E string.
Other intervals
- minor second
- major second
- minor third
- major third
- perfect fourth
- perfect fifth
- minor sixth
- major sixth
- minor seventh
- major seventh
- octave
← perfect fourth · perfect fifth →
Tritone: questions
How many half steps is a tritone?
6. On the piano, count 6 keys up (black and white) from the starting note; on guitar, 6 frets up the same string.
What is a tritone above C?
F♯. Spelled as a diminished fifth it is G♭. Above G it is C♯, above D it is G♯.
Is a tritone consonant or dissonant?
Strong dissonance. Six half steps, exactly half an octave.
Spellings computed from letter names and half steps, and checked against both. Updated September 2026.