I just started trying to learn about music theory as I'm learning to play the guitar. So as beginner's do I looked up a list of easy songs to play and I start learning away. Since I'm also trying to learn how music works and not just play other peoples songs I looked up what key these songs were in and that's when I became extremely confused.

One of the first songs I looked up was Day Tripper. The internet seemed to agree it was in the key of E so I looked up all the notes in the key of E and compared them to the notes in the song and there are certain notes, like G, that aren't in the key of E. So how is that still the same key? So is this the dumbest question ever because I can't seem to find anyone else on the internet asking it. How can a song be in a certain key but use notes not in that key?

Am I thinking of keys and scales in the wrong way, are they not that strict?

  • Please include link to the music you found on the net so we can talk about a concrete example. Regarding "key", it is useful to read up on that concept, as well as the related but distinct concepts of "scale" and "mode": en.wikipedia.org/wiki/Key_(music) en.wikipedia.org/wiki/Scale_(music) en.wikipedia.org/wiki/Mode_(music) (TL; DR: scale is a pattern to select notes from an octave; a number of scales are used so often they are known as "modes"; key refers to a tonal center ("E") which is then used as first note of one, sometimes more scales. Commented Aug 12, 2014 at 0:19
  • Regarding "Day Tripper", I'm going by this score: youtube.com/watch?v=SApO1hIVqLQ. I think what happens is that this piece is in E in a particular variant of the "blues scale". See en.wikipedia.org/wiki/Blues_scale, I believe they are using what wikipedia calls the "Octatonic" version of the blues scale. (Basically a major scale using a minor third (g) as "blue note" leading to the third g#, and a minor seventh d (rather than a major seventh d# you'd find in a regular major scale) Commented Aug 12, 2014 at 0:30
  • You asked a simple question "...are they not that strict?". I'll give you a simple answer. "No they're not!" The key, mode, whatever you like to call it, offers a framework. It tells you where "home" is. But you can play outside your own back yard. And, in anything more complex than a simple folk song, you probably will.
    – Laurence
    Commented Mar 12, 2016 at 11:45

5 Answers 5


Yes, you are thinking of the key in a way that's a bit rigid. This is perfectly understandable. When you see a song, you're trying to look at its notes and figure out what key it's in so you can understand it. It almost seems like those out-of-key notes would throw off your calculation and make it harder to figure out.

I would say even more important than key, you should understand the concept of tonal center. The tonal center is the tone that all other notes in a song will gravitate or fall back to. That's just because in most music, the writer is creating a series of notes and chords which tend to return to a main note, and a chord built from the main note. For instance, a song in the key of E has the tonal center of E. But the tonal center does not say what notes are right, or wrong, or good or bad. It just names the tone (a single note) which everything will keep gravitating back to.

Now, let's think of key not as a set of notes that are right or wrong, but as a set of notes, normally expressed as a scale, which are drawn from to write the song. That means most of the things I write to put in the song, most of the pitches and chords will by tend to come from this place. But they don't really have to. If I use other notes, it may or may not be pretty obvious to the listener that those other notes are unique and don't fit in the key. Because music has been based on the major scale for 500 years, the listener may just sort of "assume" the pitches are based on the major scale.

Over time, the concept of key has tended to revolve around a major scale this way, and any use of a chord or melody that didn't follow the major scale of the tonal center has tended to be described by its relationship that major scale. For instance, if a song made from E major scale notes always alters the 7th note of the major scale to be flat (in the key of E, this means D# would be lowered to D), this is called a b7, but you can see that this is implying that D# is the "normal" 7. We tend to use this language to understand special notes and chords even when they're used consistently. So even if the song never uses the tone D# and only uses the tone D, we will tend to say that the song is in E and it's got alot of b7. So from this I think maybe you can see why it's important to think about tonal center.

One thing that will help is learning about the minor keys, and the chords that are harmonized from them, and also learning about the different modes, and the chords that would be found in those modes. I found that when I began to understand harmony in this way, I was able to see things pretty differently because now everything falling outside of the key could be explained by saying "Oh, this comes from the minor mode of the tonal center" or "Oh this comes from the mixolydian mode of the tonal center." But that will take some practice and you may not be ready for that just yet.

As for Day Tripper, the roots of all of the chords are from the key of E, and much of the melody as far as I can recall is in the key of E. But many chords are made from pitches outside of the key of E.


Those are called "passing tones" or "non chord tones." They are very common in music and they can sound really great, like in Day Tripper :)


No you're not crazy to ask this. This is an often un-discussed feature of music, and it's actually very intelligent of you to realize it.

  • 1
    'Out of key' notes don't have to be 'passing;' or 'non-chord'. 'Day Tripper' contains plenty of CHORDS, let alone notes, that aren't diatonic in E major.
    – Laurence
    Commented Dec 31, 2017 at 18:08

When I play Beatles music, music theory actually gets in the way. John Lennon and Paul McCartney couldn't read music, they invented what they did by playing for thousands and thousands of hours on guitars and later on pianos. So I find it easiest to play The Beatles by looking for patterns on the guitar fretboard and on the piano keyboard. Most of what they play is really easy if you simply ditch conventional music theory and forget about standard notation. The Beatles just played what sounded good. Very, very, very good.

  • 3
    It's true music theory is not necessary, some might even say it's more about luck or the genius to think outside the box. My music theory professor loved the Beatles for their "accidental" music theory breakthroughs and correctness. Nevertheless, music theory saves a lot of time on composition. The down vote may have been because your answer was more opinionated than some like. Commented Aug 13, 2014 at 3:46
  • "Did The Beatles know much about music theory?" forums.stevehoffman.tv/threads/…
    – empty
    Commented Jan 27, 2016 at 18:24
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Dom
    Commented Jan 27, 2016 at 20:58

One simple rule if it sounds Good do it The chosen scale is nothing more than a guide Take the Blues scale of D Minor it does not include a B note but try composing a song with a bluesy feel in that key and use a B note hear and there

The result is very catchy

  • Hi Peter - welcome. SE is a bit different to online discussion forums. It's worthwhile looking at existing answers, as the content in your post is already here in the accepted answer - if you have a new answer it will be very welcome, but otherwise this adds no information. Thanks.
    – Doktor Mayhem
    Commented Mar 8, 2017 at 11:43
  • 1
    @DrMayhem I thought this was relevant to the question and interesting. I'm going to try out the D Minor with occasional B notes suggestion.
    – Alec
    Commented Jul 8, 2017 at 3:53

The key of a piece really solely depends on how the piece ends. If the piece ends in the key of E major, then it's in E major. It's not as simple as this, but since you're a beginner, I want to avoid lengthy explanations that may potentially confound you. Of course, you can always ask for me to go into more depth.

Notes that don't belong in the key are just non-chord tones, and are used to elaborate the melody. Without them, pieces would be painfully simple. The masterpieces you hear use stellar amounts of non-chord tones. So, don't worry about it. They're just there as embellishments. :)

  • 1
    You're just swapping the myth "all notes must be in the scale" for "all chords must be in the scale". Chromatic chords are fine, and can be completely structural within the key of the piece, not merely embellishment. To take a simple example, the Beatles song "Get Back". No-one would argue that the famous A, G, D, A riff modulates away from the home key of A major. So how do we explain that naughty G chord? We have to loosen up on these self-inflicted rules of what is "allowed" within a key.
    – Laurence
    Commented Mar 12, 2016 at 12:06

Not the answer you're looking for? Browse other questions tagged or ask your own question.