Robert Estrin - piano expert

How to Tell if a Piece is in a Major or Minor Key

Useful tips for all musicians

In this video, Robert teaches you how to determine whether a piece is in a major or minor key.

Released on January 20, 2021

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DISCLAIMER: The views and the opinions expressed in this video are those of the author and do not necessarily reflect the views of Virtual Sheet Music and its employees.

Video Transcription

Welcome to I'm Robert Estrin with a different show, as you can tell already from the theme, how to know if a piece is in a minor key. I just played the theme in a minor key, and you might wonder, how do you know when a piece is in a major key or a minor key? Well, there are certain sonic signature you may already be aware of. Something in the minor key has more of a sad or dark quality than a major key. For example, just establishing a major key compared to the same exact chord progression in the minor key, listen to the difference. Here's establishing C major. Now for C minor.

So you might just be able to figure out that a piece is in a minor key because of this sadder quality of the harmonies that minor harmonies naturally tend to. But what about a technical way to know? You see a key signature. Now, this presupposes, this video presupposes you already know your key signatures. I have not made a video yet on how to figure out key signatures, the sharps or flats at the beginning of your piece on every staff and what those mean. Well, for those of you who don't know that, I promise you I will make a video on that subject. For today, though, if you know your key signatures, everybody knows if you have no sharps or flats, or at least you should know, that you're probably in C major, if you're in a major key, because no sharps or flats form the C major scale.

So that's the sound you get. So what if that was in a minor key? What would that mean? Well, here's the interesting thing about key signatures. All key signatures share both major and minor key possibilities. So if you have no sharps or flats, it could be in C major, but it might be in the relative minor of C major. Now, what do I mean by the relative minor? Well, actually, it has to do with starting on a different note of the scale. So if you had no sharps or flats and the whole piece, instead of being centered on C, was centered on A, the sixth note of the C major scale, the sixth note of the major scale is where you find the relative minor. Another way you can find it is simply go down three half-steps from your major key. So once again, no sharps or flats could be C major, or it could potentially be three half-steps lower than C major, which again brings us to A.

So what is the A minor scale? Well, the natural minor, the pure form is simply the same exact notes of a C major scale, except starting on A. So it would sound like this. So if a piece were in C major or C minor, you might think all you need to do is figure out where the notes are centered, but there is actually a much easier way, because, generally speaking, the minor is not found in its pure or natural form. Instead, it's found in the harmonic or melodic forms, which have altered tones. That is to say that in a harmonic minor scale, the seventh note is raised a half-step, and you get this sound.

Interestingly, having a raised seventh makes an augmented second between the sixth and seventh notes. All the other notes of the scale are either half-steps or whole steps, but here you have a step and a half between the sixth and seventh note. Notice that they're three half steps apart. One, two, three.

So there you have it. Now, why is this so significant? Because if you see a piece with no sharps or flats and all over the place, you have G sharps, then you can pretty well assume that you're probably at A minor. I mentioned that there's a harmonic and a melodic form. The melodic form has two altered tones. Both the sixth and seventh notes are raised by a half-step and sounds like this.

Now, you notice I did not play descending, because the melodic minor scale descends in the natural form with no altered tones. Now, there's something really interesting about the melodic minor in that it has all the exact same notes of the major scale with the exception of the third. In other words, that A melodic ascending minor scale, once again, sounds like this. If you change one note, just change the third note from C to C sharp, now you have an A major scale. That's an interesting side note not to confuse the issue, because the A major scale has almost nothing to do with the A minor scale. They are parallel, major and minor.

But today the thing to think about is the relative minor. Once again, the relative minor is found starting on the sixth note of the major scale. So in C major, the relative minor is A minor, which can be found in either the harmonic form with the raised seventh or the melodic form with the raised sixth and seventh, which only is ascending, and descending, it reverts back to the natural minor.

So then if you have a piece with no sharps or flats and you see a lot of G sharps, perhaps a lot of F sharps and G sharps, you can be pretty well assured it's not in C major, but it's in A minor. Now, how this relates to all other keys is as long as you know key signatures, you know which specific notes to look for. For example, if you have one sharp in the key signature, which would be an F sharp, this is the key of G major and sounds like this. Define the roads of minor or G major, it's exactly the same thing. It starts on the sixth note of the G major scale.

Or you could go down three half steps from G. Either way, E minor, yes, is the relative minor of G major. So if you played all the notes of the G major scale, except starting on E, you would have the natural or pure minor scale, the E minor scale, the relative minor of G major. But that's not the way minor scales usually occur. Usually, minor keys are found in the harmonic or melodic form with altered tones. Both the harmonic and melodic minor do have a raised seventh. The melodic also has a raised sixth, but the raised seventh is the keynote, because either of those altered forms will have a raised seventh. So the seventh note of the E minor scale gets raised by a half-step, which is the D goes up to D sharp, creating this sound.

So if you have a piece with one sharp, you might assume it could be in G major, which it very well might be, but you also want to investigate the possibility that it's in the relative minor. Just count up to the sixth note of that scale to E, go to the seventh note of the E minor scale, which is D, and if you see a bunch of D sharps in your score, even though you're in one sharp and you think you should be in G major, it could very well be in E minor. This is the way to really assess whether a piece is indeed in a minor key or a major key, and every single key signature has its associated relative minor, starting on, once again, the sixth note of that major key or going down three half-steps from the tonic note.

I hope this is helpful. Study your scores, pieces you've played for years or pieces you're working on. Check to see those keynotes, and if you have a raised seventh in that relative minor, you're probably in the minor key, not the major key. I hope this has taken a rather complex subject and broken it down for you so that you can investigate yourself. Know what key you're playing in, which is extremely important to have the whole understanding of the score, the harmonies, and the structure. It can help with memory. It can help with sight reading. It's not just an arbitrary exercise in theory. It has practical elements for you. I hope this has been enjoyable for you and helpful in your music. Again, I'm Robert Estrin. This is, your online piano resource. Thanks for joining me. We'll see you next time.
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Comments, Questions, Requests:

Audrey Guild * VSM MEMBER * on February 10, 2021 @9:58 am PST
I have studied the relative and harmonic minors with my teacher and your descriptions and examples were precise and I appreciate the review. Look forward to more...
Robert - host, on February 10, 2021 @10:53 am PST
I am thinking of making a video on key signatures.
Alan West * VSM MEMBER * on January 20, 2021 @1:09 pm PST
The raised 7th of the minor scale is the altered (raised) dominant of the major key.
Ben Hundley * VSM MEMBER * on February 5, 2021 @9:48 am PST
Catherine * VSM MEMBER * on January 20, 2021 @6:09 am PST
Very helpful! I never realized there was mathematics behind it.
Robert - host, on January 20, 2021 @4:01 pm PST
You can try listening to help determine if a piece sounds like it's in the major or the minor. Then you can check to see if you're right!
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