How Many Keys are there?
12? 24? Or More?
This is an often-asked question. And it is surprising how many wrong answers there exist on the Web.
Let's clarify this issue.
There are 12 keys. Wrong!
Someone says that there are 12 keys. As an octave is composed of 12 half-steps (or semitones), it's easy to get misled and think that we can build 12 major scales starting from each of those notes and get 12 keys.
Sure, but there are more than 12 keys.
There are 24 keys, we have to include minor keys.
Wrong!
There are more than 12 keys, because we have to consider also minor keys! This doubles up our count, and so there are 24 keys.
But this is wrong as well...
Let's see how many keys actually there are
Let's start with simple considerations.
We have 7 notes:
Then we have sharp notes and flat notes.
Let's count how many keys we can create by adding those sharps and flats.
Major keys
We can have a major key without sharps and flats: C major.
Sharps
- We can have a major key with 1 sharp
- We can have a major key with 2 sharps
- We can have a major key with 3 sharps
- We can have a major key with 4 sharps
- We can have a major key with 5 sharps
- We can have a major key with 6 sharps
- We can have a major key with 7 sharps
Flats
- We can have a major key with 1 flat
- We can have a major key with 2 flats
- We can have a major key with 3 flats
- We can have a major key with 4 flats
- We can have a major key with 5 flats
- We can have a major key with 6 flats
- We can have a major key with 7 flats
How many major keys are in total?
1 (no sharps and flats) + 7 (sharps) + 7 (flats) = 15 major keys
As minor keys are relative to major keys, we have 15 minor keys as well. 15 + 15 = 30
There exist 30 music keys
Here is a table with all the minor and major keys.
You can also see these keys using the Circle of Fifths.
| Major Key | Relative Minor | Sharps/Flats |
|---|---|---|
| Cb | Ab | Bb, Eb, Ab, Db, Gb, Cb, Fb |
| Gb | Eb | Bb, Eb, Ab, Db, Gb, Cb |
| Db | Bb | Bb, Eb, Ab, Db, Gb |
| Ab | F | Bb, Eb, Ab, Db |
| Eb | C | Bb, Eb, Ab |
| Bb | G | Bb, Eb |
| F | D | Bb |
| C | A | - |
| G | E | F# |
| D | B | F#, C# |
| A | F# | F#, C#, G# |
| E | C# | F#, C#, G#, D# |
| B | G# | F#, C#, G#, D#, A# |
| F# | D# | F#, C#, G#, D#, A#, E# |
| C# | A# | F#, C#, G#, D#, A#, E#, B# |
You don't have to know all these keys.There are certain keys that work best on guitar.
Start with them.
Wait! What is Cb? Is not the same of B?
Cb and B have the same pitches, but they are called with a different name because of the enharmonics.
Interesting fact about sharps and flats in the table above
By looking at the keys table above, we can derive an interesting insight:
If we take two keys, with the second one semitone below the first, the sum of sharps in the first key and the flats in the second key is always 7
Some examples:
- A major has 3 sharps. Ab major has 4 flats: 3 + 4 = 7
- G major has 1 sharps. Gb major has 6 flats: 1 + 6 = 7
- Eb major has 3 flats. E major has 4 sharps: 3 + 4 = 7
- F# major has 6 sharps. F major has 1 flat: 6 + 1 = 7
- C major has 0 sharps. Cb has 7 flats: 0 + 7 = 7
That's surprising!
Why keys are only major and minors? What about the other modes?
As the minor key is built on the 6th degree of a major key, we could be tempted to include keys built on the other degrees: Mixolydian on the 5th degree, Lydian on the 4th, and all the other modes.
Actually, major and minor keys have a unique characteristic not present in any other mode: tritone resolution.
In the key of C, there's a tritone interval between B and F (6 half-steps, the most dissonant interval)
This interval is in the dominant chord built on the 5th degree (G7, that is G B D F)
The resolution of the tritone B F to C E (one note, B, goes up to C, and F goes down to E) can only happen to Cmaj or Amin, then they are the strongest tonal centers, more important than the other modes.
In other words, they feel home better.
Play this sequence (B F to C E) on your guitar to really understand what I mean.
This is an interesting discussion on Reddit about the superior tonal center class of major and minor keys.
How Many Keys Exist? Conclusions
I'll leave you with a cool video in which Victor Wooten, the legendary bass player, explains this stuff:
To get a downloadable pdf with all keys and stay updated, subscribe here.
FAQ
Why isn't the total number of keys simply 12, corresponding to the 12 notes in an octave?
While it's true there are 12 half-steps (semitones) in an octave, from which major scales can be built, this view is incomplete. The count of 12 overlooks the full range of major and minor key signatures that include various combinations of sharps and flats, leading to a higher total number of distinct keys.
If we include both major and minor scales, why isn't the total number of keys 24?
Considering 12 major keys and 12 minor keys (one for each chromatic note) might seem logical, but it's still incorrect. The comprehensive system of keys accounts for all possible major and minor scales that arise from unique sharp and flat key signatures, not just the initial 12 chromatic starting points. This broader view leads to a total of 30 distinct keys.
How are the 15 major keys, and consequently 15 minor keys, determined to reach a total of 30 keys?
The 15 major keys are counted by starting with C major (which has no sharps or flats). Then, there are 7 major keys that use sharps (from 1 to 7 sharps) and 7 major keys that use flats (from 1 to 7 flats). This totals 1 + 7 + 7 = 15 major keys. Since every major key has a corresponding relative minor key, this doubles the count, resulting in 15 minor keys and a grand total of 30 keys.
Why are keys like Cb major and B major considered different if they sound the same on the guitar?
Cb major and B major are enharmonic keys, meaning they produce the same pitches but are written and understood differently in music theory. They are distinct keys because they have different spellings and unique key signatures (Cb major has 7 flats, while B major has 5 sharps). These distinct signatures dictate the theoretical relationships and names of the notes within each key.
Why are only major and minor considered 'keys' in music theory, and not other modes like Lydian or Mixolydian?
Major and minor keys hold a unique position as primary tonal centers due to their characteristic 'tritone resolution.' This strong harmonic pull, created by the highly dissonant tritone interval (e.g., B to F in C major) within the dominant chord, creates a powerful sense of 'home' or resolution. This fundamental characteristic is not as pronounced or foundational in other musical modes.
Can you explain the pattern where the sharps in one key and the flats in a key a semitone below always add up to 7?
This interesting pattern reveals a symmetrical relationship within key signatures. If you take any major key (e.g., A major with 3 sharps) and then take the major key located a semitone (one fret) below it (e.g., Ab major with 4 flats), the sum of the sharps in the first key and the flats in the second key will always be 7 (3 + 4 = 7). This mathematical relationship helps illustrate the interconnectedness of key signatures.