Music TheoryHarmonyScales

What Is A Diatonic Scale?

Written by Dan Farrant

Last updated

A diatonic scale is the name we give to a type of scale with a specific formula of intervals between each of the notes. They’re the foundation of western music, but it can be confusing exactly what the definition of one is.

In this post, we’ll cover what they are, the different types of diatonic scales, as well as some of the scales that aren’t diatonic.

What Is A Diatonic Scale?

A diatonic scale is a type of music scale with seven notes (also called a heptatonic scale).

Diatonic scales must have two half step intervals (semitones) and five whole step intervals (tones) within one octave.

The two half step intervals should be separated by two and three whole steps.

If you were to play all the white notes on a piano keyboard, starting on C, you would have played a diatonic scale.

Another thing that diatonic scales have in common is that they use all seven pitch letter names (A, B, C, D, etc.) in sequence without skipping any.

Types Of Diatonic Scale

There isn’t just one diatonic scale. There are lots!

One of the things that makes a diatonic scale is that it has to contain two half steps and five whole steps, with the half steps being separated by three whole steps.

For example, you could have W W H W W W S or W W W H W W H or W H W W H W W.

Let’s look at some of these scales in a bit more detail.

The Major Scale

The major scale is probably the most familiar and easily recognizable of all diatonic scales.

If you were to play all the white notes on a piano keyboard starting on C, you’d not only play a major scale but a diatonic scale.

The sequence of half and whole steps in a major scale is W W H W W W H.

Hopefully, you also notice that the half steps are separated by two and three whole steps. This is how you know it’s a diatonic scale.

You can then transpose this sequence to start on any note, and as long as you keep the order of half and whole steps the same, you’ll have played a major scale, which is a diatonic scale.

The Natural Minor Scale

Every major scale has a related minor scale. Relative major and minor scales share exactly the same notes, but they start on different pitches.

This means that they have a different sequence of half and whole steps, but the distance between the half steps will still be three whole steps.

For example, the relative minor scale of C major is A natural minor, which has the following formula of half and whole steps: W H W W H W W.

A natural minor scale

The Modes

The musical modes are a series of scales that are based on the major scale, but each has different characteristics.

Each mode starts on a different degree of the major scale.

Even though each mode starts on a different note of the scale and has a different tonic note, they are still all diatonic scales, but the sequence of half and whole steps is shifted.

The image below of the order of whole and half steps for each mode shows that the sequence remains the same, but it shifts by one for each mode.

Interval sequences by Acf6 (Licensed under CC BY-SA 4.0)

Here is a table of the seven modes with what degree of the scale they are, the interval sequence, and an example of what notes that would be.

ModeDegreeInterval SequenceExample
IonianIW W H W W W HC D E F G A B C
DorianIIW H W W W H WD E F G A B C D
PhrygianIIIH W W W H W WE F G A B C D E
LydianIVW W W H W W HF G A B C D E F
MixolydianVW W H W W H WG A B C D E F G
AeolianVIW H W W H W WA B C D E F G A
LocrianVIIH W W H W W WB C D E F G A B

Non Diatonic Scales

When it comes to the definition of a diatonic scale, there are two camps.

The purists say that it has to have seven notes and have two half steps, and five whole step intervals.

The other view, which is broader, is that a diatonic scale is one that is in a ‘key.’ This is a more literal definition as the word ‘dia’ comes from the Greek for ‘through’ or ‘across,’ and ‘tonic’ means key.

With that definition, a harmonic minor scale could be considered a diatonic scale even though it has an augmented 2nd interval. But, for this post, I’ll be going with the first definition.

With that in mind, some non-diatonic scales include:

There are many other types of scales, but these are some of the most common ones in western music.


I hope that helps make a bit more sense of what is and what isn’t a diatonic scale. If you have any questions about anything covered in this guide feel free to get in touch and I’ll be happy to help.

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Dan Farrant, the founder of Hello Music Theory, has been teaching music for over 15 years, helping hundreds of thousands of students unlock the joy of music. He graduated from The Royal Academy of Music in 2012 and then launched Hello Music Theory in 2014. He plays the guitar, piano, bass guitar and double bass and loves teaching music theory.