What Is a Tritone — and What Is a Tritone Substitute?
- Diana Mascari
- 37 minutes ago
- 4 min read
In my many years of teaching, I’ve noticed that seventh chords can be confusing for students — especially when they begin exploring jazz, standards, and more colorful harmony.
Major 7ths and minor 7ths appear frequently in jazz and show tunes. But there is one seventh chord that appears everywhere — in folk, blues, rock, pop, standards, jazz, and beyond:
The Dominant Seventh Chord.
Because of its versatility, it’s important to understand what makes it unique.
What Is a Tritone?
Let’s break down the word:
· Tri means three (triangle, tri-state, triple).
· Tone means step (a whole step).
Put them together and you get:
Three whole steps.
A tritone is the distance of three whole steps between two notes.
Where Is the Tritone in a Dominant 7th Chord?
Every seventh chord has four parts:
· Root
· 3rd
· 5th
· 7th
In a dominant 7th chord, the 3rd and 7th are a tritone apart.
Example:C7 = C – E – G – Bb
· E is the 3rd
· Bb is the 7th
· E to Bb are three whole steps apart.
That’s called the tritone.
This is true in every dominant 7th chord — the 3rd and 7th always form a tritone.
Why Is This Important?
Because the 3rd and 7th define the chord.
In fact, you can play just the 3rd and 7th — without the root or 5th — and the chord will still function clearly as a dominant 7th.
I often call these two notes: The essence of the dominant seventh chord.
Even more interesting: You can invert them.
E and Bb or Bb and E
They still function the same way.
That tells you how powerful the tritone really is.
(If you’d like to go deeper into how chords function structurally, read my article:
It’s All About the DNA – Your Key to Better Piano Playing
Key Points to Remember
1. The dominant 7th is the most versatile seventh chord.
2. The 3rd and 7th form a tritone.
3. Those two notes (3rd and 7th) define the chord.
4. They can function alone and still imply the full dominant 7th.
The Tritone Substitute
Now the fun begins.
Because the tritone can be inverted — and because it exists inside every dominant 7th chord — something fascinating happens:
Two different dominant 7th chords can share the same tritone.
Let’s look at an example:
F7: Notes: F – A – C – Eb
· A = 3rd
· Eb = 7th
Now look at B7: Notes: B – D# – F# – A
· D# (Eb) = 3rd
· A = 7th
The same two notes in each chord: A and Eb (D#).
The tritone is identical in both chords.
And here’s the key:
F and B are three whole steps apart — a tritone away from each other.
What Does This Mean?
It means that whenever you see a dominant 7th chord, you can replace it with the dominant 7th chord whose root is a tritone away.
That replacement is called a: Tritone Substitute
Example of the Tritone Substitute in a Chord Progression
Original progression: Cmaj7 – Am7 – Dm7 – G7 – Cmaj7
G7 is the dominant (V chord).
The 3rd and 7th of G7 are: B & F
Now look at Db7:
Db7 contains: F (3rd) & Cb (B) (7th)
Db7 and G7 have the same tritone, but a different root.
So you can replace G7 with Db7:
Cmaj7 – Am7 – Dm7 – Db7 – Cmaj7
The result is a richer, more colorful harmonic sound.
In the chart below, you can see the G7 and the Db7 each have the same two notes. (3rd & 7th) which are tritones away from each other. Since the roots (letter names of each chord) are a tritone apart, they are the tritone substitute for each other.
Summary
A tritone is a distance of three whole steps between two notes.
In every dominant 7th chord:
The 3rd and 7th form a tritone.
Those two notes define the chord.
Another dominant 7th chord built a tritone away will contain the same two defining notes.
That’s why the tritone substitute works — and why it’s one of the most powerful tools in jazz harmony.
Ready to Explore Jazz Harmony More Deeply?
If you’re an adult pianist who wants to understand jazz harmony — or a musician who wants to begin composing with confidence.
I offer online jazz piano and introductory composition lessons focused on clarity, creativity, and real musical understanding.
Learn more here: https://www.mascaripiano.com/lessons
