What Chords Are in What Key, and Why?

Ever wondered why certain chords go together? This lesson explains why!

What Chords Are in What Key, and Why?
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What chords are in what key, and why? This lesson assumes basic knowledge of the Circle of 5ths.

Part 1: Basic Triads

Each diatonic scale has 7 different notes, which gives way to 7 possible triads for each key in music. A triad is the 1st, 3rd, and 5th notes of a scale played simultaneously to form a chord.

All chords are formed based on their respective major diatonic scale. A C chord is built on a C major scale, a D chord is built on a D major scale, etc.

There are 7 chords for each key, which correspond to the 7 notes in each key's scale. Some chords can be in more than one key - for example, a D major chord can be in the keys D, A, or G.

I'll use the key of C as an example:

The key of C includes the notes C D E F G A B C. Each note of the scale corresponds to a scale degree as shown:
  Note: C D E F G A B C
Degree: 1 2 3 4 5 6 7 1
You can form 7 basic chords (triads) from the notes in the key of C. Each different note is the root of a different chord.

There are 3 combinations of the 1st, 3rd, and 5th notes that will be covered in this lesson. There are 3 more, but they are not included.
Major triad: 1 3  5
Minor triad: 1 b3 5
Diminished triad: 1 b3 b5
Your first chord will be a C chord, because C is the first scale degree. Now, since this is a C chord, it will be based on the C major diatonic scale. Take scale degrees 1 3 5 as shown below:
  Note: C D E F G A B C
Degree: 1 2 3 4 5 6 7 1
* * *
This gives you notes C, E, and G. Since all 3 of those notes are in the key of C, you do not have to modify them to fit, and you have a major triad (1 3 5). So your first chord is C major.

The second chord will be a D chord, because D is the 2nd scale degree. It's based on the D scale, which is D E F# G A B C# D. Now, take 1 3 5 of this scale:

Note: D E F# G A B C# D
Degree: 1 2 3 4 5 6 7 1
* * *
This gives notes D F# A. This presents a problem - F# is not in the key of C! In order to keep this chord in key, we have to flat the F# (lower it by 1/2 step) down to F natural. This gives D F A, which is scale degrees 1 b3 5 of the D major scale. 1 b3 5 is the formula for a minor triad. Therefore, your second chord is D minor.

The seventh chord will be a B chord, because B is the 7th scale degree. It's based on the B scale, which is B C# D# E F# G# A# B. Now, take 1 3 5 of this scale:
  Note: B C# D# E F# G# A# B
Degree: 1 2 3 4 5 6 7 1
* * *
This gives notes B D# F#. D# (3) and F# (5) are not in the key of C, and must be flatted to D (b3) and F (b5), respectively. This gives us scale degrees 1 b3 b5, which is the formula for a diminished triad.

Based on these examples, you can figure out the rest of the chords. However, they always follow a pattern:
1 - major
2 - minor
3 - minor
4 - major
5 - major
6 - minor
7 - diminished
By applying this pattern, you can quickly figure out that the chords in the key of C are:
Cmaj
Dmin
Emin
Fmaj
Gmaj
Amin
Bdim
All the notes contained in the above chords will be in the key of C.

This pattern works for any of the keys in the Circle of 5ths. It does not, however, cover any scales that are not the major scale (such as the harmonic minor scale, for example. That has its own pattern of chords).

Part 2: Extended Chords

Okay, so you've got the basic triads down? Great! Now on to extended chords. First, you must learn the formulas for the 4 types of 7th chords.
      Major 7th: 1  3 5  7 - Abbreviation: maj7
Minor 7th: 1 b3 5 b7 - Abbreviation: min7
Dominant 7th: 1 3 5 b7 - Abbreviation: 7, dom7
Minor/Major 7th: 1 b3 5 7 - Abbreviation: min/maj7
Now, let's return to our first chord. We know it's a major chord from Part 1. We can now figure out what type of 7th chord it is using the same method.
  Note: C D E F G A B C
Degree: 1 2 3 4 5 6 7 1
* * * *
Your notes are C E G B, all in the key of C. No changes are needed to the notes, and so this is a maj7 chord.

Our second chord was a minor chord in Part 1. Let's take it to the next level, a 7th chord.
  Note: D E F# G A B C# D
Degree: 1 2 3 4 5 6 7 1
* * * *
The notes are D F# A C#. F# (3rd) and C# (7th) are not in the key of C, and must be flatted on down to F natural (b3rd) and C natural (b7th). Therefore, your scale degrees for this chord are 1 b3 5 b7. This gives us a min7 chord.

Our 5th chord is a G chord - let's find the 7th.
  Note: G A B C D E F# G
Degree: 1 2 3 4 5 6 7 1
* * * *
Our notes are G B D F#. F# (7th) must be flatted to an F natural (b7). Our scale degrees are 1 3 5 b7, which is the formula for a dominant 7th chord. Our 5th chord is G7!

The seventh chord is a Bdim chord as shown in Part 1. Extending this chord, we find that it is a min7(b5) chord.
  Note: B C# D# E F# G# A# B
Degree: 1 2 3 4 5 6 7 1
* * * *
This gives notes B D# F# A#. The D#, F#, and A# are all flatted 1/2 step to give degrees 1 b3 b5 b7. This is the formula for a min7(b5) chord, also known as a half diminished chord.

Using the same method you can figure out the other chords. They also follow a pattern. That pattern goes as follows:
1 - maj7
2 - min7
3 - min7
4 - maj7
5 - dom7
6 - min7
7 - min7(b5)
And, as you may have guessed by now, the chords in the key of C are:
Cmaj7
Dmin7
Emin7
Fmaj7
G7 OR Gdom7 (they are the same chord)
Amin7
Bmin7(b5)
That's all for now. Feel free to PM me if you have questions, or visit the Musician Talk forum!

178 comments sorted by best / new / date

comments policy
    ronnie_sjr
    Omg. Great lesson, it's very easy to comprehend and very applicable indeed. Nice job dude! =)
    jof1029
    gret article SilentDeftone, its easy to understand and has great info. too bad lessons dont make the front page, im sure many people would like to read this.
    SilentDeftone
    Thanks Corwinoid! I tried to make this as comprehensive as possible. Although perhaps I should have included a Circle of 5ths section, I think that is another lesson in itself.
    isaluteu: it'd be cool if you posted a lesson on effective ways to use out of key chords : )
    http://www.ultimate-guitar.com/columns/m... ml Credit to Raindog for that one
    sailsingle4u
    very good. seems complicated though. or is it just dumb me. once you know the above, where does that get you; what are you able to do with this knowledge, if i were to remember it, how does it apply .....keep up the good work, great explanations, good teaching....just a dumb learner....thanks....
    pibws001
    It means that all those chords sound good played simultaneously or in order with the C chord or C major scale
    SilentDeftone
    isaluteu: ^i read that one a while ago, but it is now deleted. :\ [POSTED: 04 December 2004 - 17:57]|
    No it's not.
    E B C#m - A E - E B C#m F#7 B Clearly, he's in the key of E. However, he doesn't use an F#m7, he uses an F#7, and it doesn't sound dissonant. Is this because it resolves to the B?
    Ah, interesting question! That's what's known as a secondary dominant chord. Secondary Dominants Basically, the V7 chord leads very strongly to the I chord, because the V7 chord contains the 7th tone of the I chord's major scale. The 3rd in the V7 chord is the same as the 7th in the I chord. 7ths almost ALWAYS resolve up to the root note. This is called tone leading, I believe. Anyways, on to your question. In the key of Bmaj, the V chord is an F# chord - and since V7 chords resolve well to I chords, your F#7 chord resolves extremely well to B. When writing this chord, you'd write it as V/V instead of II7, because it's the V chord of the V chord. Also, it works relatively well because the temporary key change is minimal. An F#7 chord is different from an F#m7 chord only in the chord's third. An F#7 has A#, while F#m7 has A natural. Take a look at your key - E. E has 4 sharps: F# C# G# D#. The next key over, B, has 5 sharps: F# C# G# D# A#. Therefore you're only changing one note, it's not a large change at all. Hardly noticeable if you don't analyze the song, eh? I hope that was clear enough, I assumed you knew some theory!
    Corwinoid
    Dard: Diatonics can be kind of difficult to understand without actually seeing them written in music, and even then it takes some time to get a good handle on what's going on. The really confusing points are chord 'formulas', how chords are built out of a scale, and a few other points I won't bring up because they weren't in the original topic. Basically, your major/minor unaltered chords are built by taking every other note of a major scale, starting at any given note. (ie. A-C#-E, for A major, this can be continued until you use all 7 notes in a scale, yielding some variation of a 13th... but that's a little complex). Understanding the chord formulas is the next step, for instance the 'formula' for a minor chord is 1-b3-5. These are alterations compared to that chord's OWN major scale, often that's not made clear. For instance, the scale A major is A B C# D# E F# G#, if you take the 1st, 3rd and 5th you have A-C#-E, Amaj. Applying the minor formula to that, you would flat the 3rd, changing the C# to a natural C. Giving, A-C-E, Amin. It's pretty easy to see that that fits the Cmaj scale that Def demonstrated with. Let us know if it was something else that was confusing you. Overall Silent, great post 5* -- C
    SilentDeftone
    dragon1552000 wrote: Hey, nice article. The only correction I would like to make is that you labeled the 4th and 5th scale degrees as "major". They are actually called perfect 4th's and 5th's. I know i'm being technical but my theory teacher would have a hissy fit if I made that mistake haha. So in otherwords it goes: I - Tonic ii - Minor, major, Aug. or Dim iii - Minor, major, Aug. or Dim IV - Perfect (Or Aug. or Dim.) V - Perfect (Or Aug. or Dim.) vi - Minor, major, Aug. or Dim vii - Minor, major, Aug. or Dim VII - Ocatave (Tonic) I know i'm being very technical but I think if the UGer's are to learn something, they mind as well learn it correctly and completely. Thanks, Aaron
    I am correct. The chords are major in tonality. You are referring to intervals - the major scale has perfect 4th and perfect 5th intervals. Not chords. Perhaps you should find a better source to do your "correct learning" from. -SD
    crowmagnum
    I'm in mid fifties and just started playing again a few years ago after a 30 year hiatus. Thank you deftone. U have cleared up so much I can't even describe it. This is the stuff I have never found in any method books. I have never seen this info presented so concisely and completely. I know there is alot more to it but man what a GREAT place to start. Anybody on this board who doesn't grasp these concepts should sit down and study them like they have never studied before (well maybe med school or bar exam excepted) If u want to play, this stuff is worth its weight in gold. thanks again. And if you count on tabs I urge you to learn to read notation. If you r in the least bit serious about music it will set u truely free. (as corny as that sounds)
    Zatchel
    This is pretty much the best lesson in the entire lesson section... throw out everything else because it is crap. The author defined everything that he stated in the title. Thank you.
    akosininio
    Thanks man, the only thing I see missing here is chord progressions maybe? Very helpful nonetheless. Thanks!
    2dor
    great lesson...helps a lot...this things can be applied to seewp arpegios also?...progressions of arpeggios...
    DEATHbyBLOOD
    i'm grateful for the fact you took yout time to write this lesson, it's one of those things you read and it helps you connect the dots in your head and all of the sudden you have this huge new understanding of the guitar. thanks dude!
    one vision
    Good stuff, I never knew there was a pattern, I always had to wreck my brain trying to figure it out.
    reGacc_0134
    um...im confused...ill work it out eventually, anyway, good lesson and good job working on this
    slash&angus
    i Don't understand how do you make your diatonic scale. Don't need just the name of the notes but the places on the fretboard.
    hersheybar255
    damn sd, this made alot of sense but when u started going all complex in the comments section about people personal questions about theory i got totally friggin lost in everything.. did u graduate from a school of music? if u didnt then i swear ur like a guitar god
    hersheybar255
    btw thanks for the lesson. ive read a couple times before a while ago and couldnt make anything out of it. i got it this time though. itd take me forever though to come up with a bunch of chords from different keys. and i dont know how i would apply them without memorizing them? could i also ask u another question? how come u did the 1 chord, then the second, then jumped to the seventh? i didnt understand that
    SilentDeftone
    The 3rd-6th chords can all be derived in the same way as the first two. The seventh creates a new chord (m7b5). No, I did not graduate from any music school. Just learned from UG and The Real Book
    selinaguitar
    Thank you SO much SilentDeftone!!! I've struggled with learning music theory on my own and nearly quit guitar because it was giving me such a headache. This thread and the comments cleared up so much of my confusion!!
    snuggleblade
    the_guy wrote: this is the greatest lesson in the world. i now understand that you don't just throw random chords together. you are the greatest person who ever lived
    This has to be sarcastic. I hope it is because if you are serious I will say this: MUSIC HAS NO RULES. And music theory is simply a reference. I mean one of the best bands ever - The Butthole Surfers - used to tune their guitars by throwing them up in the air and however they landed, that would be their new tuning. So there is your music theory lesson from me.
    si!
    this really cleared a lot up for me, thanks a ton.
    FretZippy21
    Thanks Deftone, it helped me in someways, but I was looking for a way to "tell what key I am in" Because I really don't udnerstand, and nobody can explain it, if you can help PM me but it's 2:30 AM here so Im off to bed, I'll love to discuss this with you, if you do PM me. Later.
    Johnljones7443
    Nuums wrote: 'sus' means Suspend.. You take out a note from a chord. If it is, lets say, Asus8
    Lol, Asus8?
    Metatron wrote: Did you forget about augmented triads?? Augmented Triad - 1, 3, #5
    No augmented triad occurs within the major scale.
    Metatron wrote: Edit : Btw, I'm still confused about the theory of a suspended chord.
    A suspended triad is a triad where the third is replaced with a different tone. A sus2 chord replaces the third with the second, a sus4 chord replaces the third with a fourth. Cmaj: C(1) - E(3) - G(5). Csus2: C(1) - D(2) - G(5). Csus4: C(1) - F(4)- G(5). Does that clear it up?
    muzonerd
    vHey, nice article. The only correction I would like to make is that you labeled the 4th and 5th scale degrees as "major". They are actually called perfect 4th's and 5th's. I know i'm being technical but my theory teacher would have a hissy fit if I made that mistake haha. So in otherwords it goes: I - Tonic ii - Minor, major, Aug. or Dim iii - Minor, major, Aug. or Dim IV - Perfect (Or Aug. or Dim.) V - Perfect (Or Aug. or Dim.) vi - Minor, major, Aug. or Dim vii - Minor, major, Aug. or Dim VII - Ocatave (Tonic) I know i'm being very technical but I think if the UGer's are to learn something, they mind as well learn it correctly and completely.
    Hey, Aaron i think you've got your scale degrees and modes and tonalities mixed up If we're going to get technical then naming the degree's would go: 1 = tonic 2 = super tonic 3 = mediant 4 = sub dominant 5 = dominant 6 = submediant 7 = leading note and then you have tonality 1 = major 2 = minor 3 = minor 4 = major 5 = major 6 = minor 7 = diminished and then you have the modes 1 = Ionian 2 = Dorian 3 = Phrygian 4 = Lydian 5 = Mixolydian 6 = Aeolian 7 = Locrian thats used just for describing what you hear. If you were to call something a perfect 5th, that would only be used in representing the interval of 1 to 5. like C to G. just the same as a perfect 4th is the interval of 1 - 4 (in C maj = C to F) hope that helps
    victoryaloy
    heres a much easier way to figure the chords out, I got this from Johnljones7443: C - D - E - F - G - A - B - C - D - E - F 1 3 5 1 3 5 1 3 5 1 3 5 1 3 5 1 3 5 1 3 5
    Calvinexp
    spectacularly written thanks a lot i learn so much by this lesson. you cleared up so many questions i had. and the lesson was easy to understand thanks again.
    amroze
    Great lesson! There are so many things to learn.. I think is a basic and a must for guitar players!
    simonzwaan
    Scartissue wrote: My English is not that bad (i think), but I can't use this because of some words. Is there a possibility to convert this text into a Dutch text? Hope so!
    I could translate it lol
    sharene
    great lesson! I was just wondering can you play a minor scale over a chord progression based on the major scale?
    SpikOteZ
    Thank you very much for posting this lesson! I have found it really useful. Cheers SilentDeftone \m/
    Xtreme57
    I do not understand how to find the chords in the other keys not listed. I'm pretty new a this, and yeah ... don't get it. Please help!
    Saofan12
    best lesson i've seen on explaining chords, easy to understand a big help, thanks a lot dude.
    XxPunkMafiaxX
    you are officially the most useful music teacher ive had! thanking you greatly il never remember all this, but il keep referring back to it whenever i write a new song hehehe
    melvg
    hi guys, er, i have trouble understanding what are Degrees, Triads etc.. sorry, i dont have any theory lessons before. Where can i start learning all the theories in this websites?? which article to start first?? need some help guys. thanks in advance.