Interval · TT · 6 half steps
The tritone
A tritone is six half steps, exactly half an octave: C up to F♯ or G♭. Restless, and it wants to resolve.
- Half steps6
- Letter names4 or 5
- From CC–F♯ / C–G♭
- Inverts totritone
The tritone on the staff
An interval’s number counts letter names from the bottom note to the top, both included: C, D, E and F is four, a fourth. On the staff, one note is on a line and the other in a space: from a line, it lands in the second space up; from a space, on the second line up.
A tritone can be spelt two ways. Over four letters (F up to B) it’s an augmented fourth; over five letters (B up to F) it’s a diminished fifth. On the keyboard they’re the same two keys; the music around them decides which spelling the composer uses.
Each example below plays the two notes one after the other (a melodic interval), then together (a harmonic interval).
On the piano
Count half steps: every key, black or white, is one half step from the next. From middle C, the tritone is the 6th key up, F♯ (also called G♭).
From any key, count six half steps, or go up a perfect fifth and come down one key. On the white keys there is only one tritone: F up to B, or B up to F.
White-key tritones: F–B and B–F. Every other tritone needs a black key.
How a tritone sounds
The tritone is tense and restless: it hovers between a fourth and a fifth and pulls hard to resolve, outwards or inwards. It was nicknamed diabolus in musica, the devil in music, and is still used for anything unsettled, from Halloween music to sirens.
In harmony, it’s a dissonance: restless, wanting to resolve.
Tunes that start with it
- “Maria” from West Side Story starts with a tritone: “Ma-ri-” leaps up a tritone, then “-a” rises a half step to a fifth.
Hum the tune’s first two notes and you have the interval: a quick way to sing one before you play it.
Where you’ll meet it
The tritone sits in every dominant seventh chord: in G7 (G–B–D–F) it’s B–F. B pulls up to C and F pulls down to E, landing on C major. That pull is what makes V7–I the strongest way to end a phrase. Spelled as letters, it’s an augmented fourth (F–B, three whole steps, hence “tri-tone”) or a diminished fifth (B–F).
Turned upside down, with the bottom note moved up an octave, a tritone becomes a tritone again: 6 and 6 half steps make an octave.
To read it fast in real music, practise intervals the way you read words: as shapes. Level 6: fourths and fifths in the free sight-reading exercises has plenty of them.
Quiz: the tritone
Ten questions: name the interval on the staff, among its neighbours, and play a tritone above a written note on the piano below, a MIDI keyboard or your computer keys.
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A tritone above every note
| From | A tritone up |
|---|---|
| C | F♯ |
| D♭ | G |
| D | G♯ |
| E♭ | A |
| E | A♯ |
| F | B |
| F♯ | B♯ |
| G | C♯ |
| A♭ | D |
| A | D♯ |
| B♭ | E |
| B | E♯ |
Each one is spelt with the fourth letter up (an augmented fourth), which is why some need a sharp or flat that looks unusual, like F♯ up to B♯.
Questions
How many half steps are in a tritone?
6 half steps, or 3 whole steps. Count every key, black and white, from the bottom note up to the top one: C to F♯ (or C to G♭) is a tritone.
What is a tritone above C?
F♯ (an augmented fourth, spelt with the fourth letter up) or G♭ (a diminished fifth, spelt with the fifth letter). Both are the same key on the piano.
What is the inversion of a tritone?
A tritone again. Move the bottom note up an octave and the six half steps become six: tritone and tritone add up to an octave.
How do you recognise a tritone on the staff?
One note is on a line and the other in a space: from a line, it lands in the second space up; from a space, on the second line up. That tells you the letter distance; then check the sharps, flats and key signature to tell perfect from augmented or diminished.
What song starts with a tritone?
“Maria” from West Side Story starts with a tritone: “Ma-ri-” leaps up a tritone, then “-a” rises a half step to a fifth.
Hear every interval in real music
Pianomi, a free sight-reading app for piano, writes new pieces at your level and listens to your MIDI keyboard, so intervals become shapes you read without counting.