I have been building chords in maj7 and stringing them together in what sounds good to me. I like the sound of this progression and am curious as to how to determine what key it is, if any. I am very new to all this. Thanks, MikeB

  • 1
    When you stop on each one in turn, which sounds more like that's the end of the sequence? That's always a good criterion. Probably the C.
    – Tim
    Commented Jan 3, 2019 at 9:40
  • I hear a-minor. The sequence is almost the Lament Bass. en.m.wikipedia.org/wiki/Lament_bass Commented Jan 3, 2019 at 20:23

4 Answers 4


Probably in key of C Major.

If you change chord from AMaj7 to Amin7 and from GMaj7 to GMaj, then all the notes of this progression will be from key of C Major, however you can proceed without changing the chords and still keep the melody in key of C and borrow other scale notes as needed for the song.

This is how I determine the key of the song when provided the chord progression.

  1. Normally most songs will end in tonic chord, in this case C Maj
  2. Most notes will fit into a single diatonic scale, in this case C Maj has all notes from this progression except AMaj7(two notes) and GMaj7(one note)

You can learn basics of Major and Minor scales and circle of fifth to get some ideas on finding key for a given progression.


Normally you try to match the collection of tones from the chords to the tones of a key signature.

If you are picky about "being in a key," then you want to look at how the leading tone of the scale is being treated. If there isn't a leading tone, then it may be more appropriate to talk about which mode the music is in.

There may be chromatic chords in a progression complicating the matter of matching chords to a key signature.

Also, some music simply isn't in a single key or mode. In those cases you need to decide whether the best description is modulation, ambiguous tonality, polytonal, or atonality.

Amaj7- Gmaj7- Fmaj7- Cmaj7

With a short list of (diatonic seventh) chords like this you can first consider each chord as a possible tonal center. So, A, G, F, or C major could be possible keys. Then see if any of the other 3 chords fit into one of the potential keys.

  • no other chords fit into A major
  • Cmaj7 fits into G major
  • no other chords fit into F major
  • Fmaj7 fits into C major

That gives us G or C major possibly. But there isn't a dominant chord for either of those two possible keys. In fact with all maj7 chords we don't have a dominant - it sort of negates dominant harmony - and if you are picky about your tonality you must say a key cannot be defined with these chords. Or you might say the sense of key is vague.

The order of chords matters. The Fmaj7 Cmaj7 is the only two chord change that fits a key. All the others are chromatic. That makes a good case for a C tonal center.

The chord roots C, F, and G fit nicely into C major, but the F# of the Gmaj7 is outside the key.

I think you could call this a sort of ambiguous C major tonality. It's mostly non-functional meaning it doesn't work with dominant to tonic harmony.

Two devices...

  • The Amaj7- Gmaj7- Fmaj7 sequence is an example of parallelism or planning.
  • Assuming the progression repeats Cmaj7 | Amaj7 is a relationship called a chromatic mediant.

...are common for this kind of non-functional harmony.


This was a fun challenge. So after fiddling with this for a while and adding a bassline that kind of changes the function of the chords I actually put it in A Minor.

Playing this on the piano, I basically played the listed chords in the right hand, with different notes in the root in my left, basically changing their function. So the chords on top are what I played with my right hand (chords listed) and below is what I played in the bass;

Amaj7- Gmaj7- Fmaj7- Cmaj7(2nd inversion)


Obviously I added some extra inflection to make it sound more like a proper bassline but that's the gist. I'll explain the function of that;

So I started with A in the root for the Amaj7, then I put the D which is the 5th of the Gmaj7 basically just because it works better in the line. I could put G there instead (same function) but then the line would be A-G-G-A which would be boring. So now down to the juicy stuff. I put the G in the root of the Fmaj7 to basically change the function and make it act as dominant 7 chord (leading to C). I tried to look up the name of a iv chord with the dominant in the bass and I couldn't find one other than just "slash chord". The function of a slash chord is basically the same but not quite as specific to this situation. Anyways, with the G in the root you want to go to C but if you put A in the root the Cmaj7 basically becomes Am9

I know I kind of cheated adding to the chords since technically that wasn't a part of the question but I figured it was an interesting take.

  • If you're curious about Fmaj7/G, often that particular voicing gets labelled G13sus (G as root, F as 7, A as 9, C as sus4, E as 13).
    – user45266
    Commented Oct 15, 2019 at 4:30

Technically speaking, just a chord progression alone is insufficient to determine the key without other context.

The key is where you feel the song settles naturally, which is decided by the phrasing of the melody and song structure. As a rule of thumb, usually the I chord is where the chorus of a song resolves to, verses will sometimes start or settle on other chords.

However, given your 4-bar chord progression, I would probably assume first that the song is in C, since that would mean the chord progression uses the VI / V / IV / I chords which are the 4 most common chords to combine in popular music (technically vi minor but VI is common too, and most importantly it has the dominant (V) and subdominant (IV) chords). But I could also write melodies or song sections that would make that progression sound front-heavy and want to sit on that first chord, so it sounds like a I / bVII / bVI / bIII, it all just depends on what else is going on.

For songwriting advice in general, I wouldn't focus too much about consciously finding a key at first, just improvise humming over the chords as they pass to find some melody or riff that you can latch on to and develop, and after stringing a few bars of that together you'll feel where the underlying chords want to resolve to. Many people also start songwriting the other way around, just thinking up a melody in isolation and then figuring out the chords by elaborating on that melody to feel how you would expand arpeggiated chords from it.

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