When composing, I generally start with C Major to be simple, but very often, I can hear that in the melody another key is suggested.

Here is such an example :

enter image description here

  1. The melody starts by leaping to the VI degree of C Major (III of F Major)
  2. The melody does not use a B Flat which is one particularity of F Major
  3. The II & III degree of C Major are not used either.

Why is this melody in the key of F & not the key of C ?

  • 2
    I dropped it to single line to save space, original on click-through. Hope you don't mind.
    – Tetsujin
    Sep 1, 2023 at 13:13
  • No problem at all, thank you very much :)
    – amcstomp
    Sep 1, 2023 at 13:42
  • Also, there are more C's than F's in the melody :-)
    – Jos
    Sep 1, 2023 at 14:52
  • 6
    "The melody does not use a B Flat which is one particularity of F Major": it also does not use B natural, which is one particularity of C major.
    – phoog
    Sep 1, 2023 at 21:00

4 Answers 4


Even though your accepted answer says they hear it more as 3/4, writing or hearing it in 3/4 is irrelevant to why this sounds like the key of F. Not only that, they actually changed your original rhythm to adapt it to 3/4. Two half note A’s were changed to quarter notes.

It legitimately sounds like 4/4 as written. Even in 4/4 the reason your piece sounds like F is because it is in F. The entire melody gravitates to and resolves to the note F on several downbeats. It also implies harmony in the key of F. Your first 2 notes are C A, outlining an F triad with no root. The leap leading from A to F going into bar 2 and the fact that that melodic phrase ultimately ends on an F, not to mention that the entire example ends on an F note preceded by an E, the leading tone of F, is enough to say that this heavily implies F. There is no hint of the key of C here at all.

If you were to leave this as is or put it in the key signature of F it wouldn’t matter because there are neither B’s or Bb’s in this melody.

EDIT: In reference to the answer provided by @Mixnik and the comment by @KarlKnechtel I decided to write a 4/4 version with more traditional melodic flow and stresses for consideration. Please excuse my poor penmanship, I drew this on a tablet screen with my finger.[enter image description here

EDIT #2: Here is the same example with an anacrusis for the C melody notes:

enter image description here

  • 1
    @amcstomp Hi, first see my most recent edit to the first two paragraphs regarding the time signature. Secondly, I dislike the word “rules” when discussing composing. We do what sounds good and right to us and that should be enough, unless you are trying to do something very specific. It is not necessary to outline or imply harmony when composing, it is also not necessary to stick to the seven notes of the diatonic scale. If outlining harmony happens naturally then that’s fine. In your case you are using the notes of an F triad in your writing as well as resolving your melodic phrases to F. Sep 1, 2023 at 19:28
  • 1
    @amcstomp I also wanted to point out that the questions you asked in your comment are better off posted as other separate questions because there is an awful lot that can be said to reply to them, too much to answer in comments alone. Sep 1, 2023 at 19:36
  • Thank you for your answer too, I now see that you there must be melodic "rules" for writing in a key without mixing into others. That means that If i wanted to write in C, i should have outlined harmony belonging to the C key (tonic triad) at first.
    – amcstomp
    Sep 1, 2023 at 19:36
  • I understand & Thank you. By rules i meant if wanting to write in a specific way, and I fully agree, there can't be any hard written rules for "music" as vast as it is.
    – amcstomp
    Sep 1, 2023 at 19:39
  • @amcstomp one way to write a melody in C is to take this melody and move every note up a perfect fifth.
    – phoog
    Sep 1, 2023 at 21:14

I think you main problem with this music is that, although written in 4/4, the piece itself sounds to have a more 3/4 feel. This 3/4 effect makes it so the first beats of each measure mostly land on F or one of the notes of its major triad (F A or C), thus giving you a sense of F major even though a B flat is never played.
Notice that B flat itself is not a defining factor of F major, as we see here, but instead this F major sense implies the existence of B flat. Also notice that after every C the melody lands on one of the notes of F's major triad, so although the C may be played frequently, it is used to imply F major even further, especially in the C to A intervals since the C sounds like it is played on the last beat of the measure.
I have written below what the piece sounds to me which should clarify my points a little:Musical extract transcribed as heard

  • If i understand correctly, tonality in only a melody depends on what Triad is implied on the strong beats in addition to the other played notes belonging to that specific key. How does "implying" a triad work, is it playing one of it's notes on strong beats then ?
    – amcstomp
    Sep 1, 2023 at 15:59
  • 1
    @amcstomp this piece does not imply a chord/triad, but implies the key of F major. It does so by using the notes of the F major triad on strong beats and using the 5th degree of the scale at the end of the measure. By "implying", I mean you never explicitly used the key of F major in your notation (neither have I) but the music itself guides the tonality. Please note that this definition of "implying" is not the technical definition (if there is one) but is used merely to describe this effect as best I can.
    – Mixnik
    Sep 1, 2023 at 16:45
  • There are many ways to "imply" a tonality, I have just stated the ways in which this extract of music does so. You may encounter a piece of music which implies a tonality but does not use any methods outlined above. Nothing comes to mind at the moment but creativity is rarely so easy to summon
    – Mixnik
    Sep 1, 2023 at 16:50
  • 1
    I think you are projecting the 3/4 onto this. You even changed some note durations to accomplish it although what you wrote does sound correct and logical. It is not necessary. It is logical as written in 4/4 and still sounds like the key of F. The tonic melody note doesn’t always have to fall on a downbeat. Sep 1, 2023 at 20:12

The most important thing to consider is not whether the piece includes Bb or not, but which note is serving as the tonic, or home tone.. This is the note that, simply put, sounds like the end of the song. It has a very stable sound, and it gives us a feeling of rest or conclusion. Wouldn't you agree that your last note, F, gives us that feeling that the melody is done?

Now, try a little experiment. Replace your last note with a C. Does that note give you a feeling of rest and conclusion, or does it give you a feeling that the song is unfinished? Were you to play it for 100 listeners, 99 would likely say that the note F sounds final and the note C does not. For this reason -- our perception of finality -- F is the tonic for this song.

To be correct, we should add the B-flat to the key signature to show that F is in fact the tonic (even if there are no B's in the song).

Why is F the tonic? Why can't it be C? There are two reasons that stick out. First, we are very used to the interval of the perfect fourth (here, C to F) working as 5^ 1^, or sol do for solfege readers. C-F tends to happen a lot in F major as 5-1, and much less frequently in C major as 1-4. Another reason suggested by Mixnik is that the notes of the F major triad appear on many strong beats, and this tends to set up F as the tonic, too.

If you wanted to write this in the key of C major, slide every note up 5 steps. Your opening sixth would be G-E, and all those parts that used to outline the F triad would now outline the C major triad. Your final note would be C, and it would really and truly sound like the tonic.

  • Hi, thank you for your answer. By interval of perfect fourth (C -> F), do you mean to say that C is the Dominant of the F key and because they are so closely tied, implying an F triad just sets it all on F ?
    – amcstomp
    Sep 1, 2023 at 19:56
  • Yep that is exactly it
    – nuggethead
    Sep 1, 2023 at 20:49
  • @amcstomp regarding "The most important thing to consider is not whether the piece includes Bb or not": we have seen a few questions here about the fact that the Star Spangled Banner, if played in the key of F, has more B naturals than B flats. It's very common for melodies to depart from the diatonic scale. The critical factor is in the second paragraph here: which note is the "home" note?
    – phoog
    Sep 1, 2023 at 21:20

Mainly agreeing with other answers but I would like to mention one further point.

The tonality is determined by the note which gives a feeling of "finality". To me this is definitely F in your example, because

  • the piece finishes on F, with a (possible) implied dominant harmony just before;
  • there are many F major arpeggios (4 in 8 bars, if you count upwards and downwards arpeggios separately);
  • additionally, the piece begins with two notes of an F major triad.

Others have basically said all this. But I would like to point out that (at least to my ears and brain) the feeling of F major is SO strong here that you could even have a B natural without greatly upsetting it. Suppose you take the minim (half note) A in bar 5 and replace it by two crotchets (quarter notes) A and B natural. To me, the tune would still be in F major, with a momentary hint of a possible (but unfulfilled) modulation to C major in the middle.

If you made this change (and if you agree with me that the piece is still in F major) then the "academically correct" way to write it would be with B flat in the key signature, and an accidental natural on the B I have just referred to.

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