How do you figure out what key a song is in?

This question comes from an e-mail:

The second question is more of a clarification on how you would recommend starting to recognize scale degrees, specifically the first note of a song. I see a few ways to approach this seemingly simple task:

- Presume that the first note starts on the first degree, since most songs start on the I chord.
I can then build a melody using scale degrees relative to this "do". I suspect this is not right and would possibly result in me unintentionally transposing the tune to some other key. This approach also doesn't get me to the same "answer", which you get to in many cases. For example, on page 14 of "Learn to Play by Ear", the first degree in your example for The First Noel is mi as opposed to do. So I ask myself, "How did he know it started on mi?"



The only real way to figure out the key is by analyzing every note in the song. This is because songs can seem to be in one key and then after a few chords it will seem to be in another. How do you decide which of the two keys is the correct key?

The only real way is through experience.

There are some general rules though.

1) If a song starts and ends in a particular key, then it's in that key.

2) If it spends most of the time in one key, but one section is in a different key, then it's in the first key.

Some songs move constantly. "All the Things You Are" starts and ends in one key, but moves through about seven key changes (I can't quite remember, but it's a lot).


How do you tell a song starts in a particular key? Because of the notes of the melody. If all of the notes of a melody are in a particular key, then you know it's in that key.

For example, there are two half-steps in every major key.

In the key of C, the half-steps are between B and C, and between E and F. If the melody starts with a half-step between the first two notes, you'll know almost immediately what key you are in, because you have a 50% change of being right. (There are exceptions, such as notes that go outside the key, but let's keep this simple)

I would say using half-steps is a great way to find out what key you are in. Also study songs that have half-steps prominently in the first few notes of the melody, such as "The Song is You".

The other way to easily tell what key you are common chord progressions. If a song starts with I vi, ii, V, you'll know within the first two measures what key you are in. Songs such as "The Way you look Tonight" use this common chord progression right at the beginning of the song, which makes it easy to tell what key you are in.

Some songs such as "Satin Doll" use the ii, V progression. So it doesn't start on the I chord, but after a few measures, it's obvious that this progression has to be ii, V. Study common chord progressions, memorize the chord changes to famous songs, and you'll start to be able to immediately figure out what key you are in.

It goes without saying that memorizing all 12 major keys is the first step.

OK, back to the question:




- Option 1: Look at some sheet music to see what note the song started on when the music is transposed to the key of C.


Yes, the key signature in sheet music is the right key 90% of the time. But watch out for relative minor. If the song is in the key of C, but the first chord is Am, it's probably in the relative minor of C, which is Am. Very rarely you'll also see modal songs, where the root chord doesn't match the relative major. The most common of these is the dorian mode -- but this is something kind of esoteric. I don't think you should worry about that. But do learn the relative minor for each key. It's basically the six chord, so if you know your chords in all 12 major keys, you'll know your relative minors as well.
Back to the question:


- Option 2: Listen to some music and aurally try to see if you can match the first note to one of the notes in the middle C scale.


When I play by ear, I just hit a piano key. If the melody note that I'm looking for is higher or lower, I move up or down respectively.

But as your musical knowledge grows, you make more sophisticated judgments. Was it up a minor third, or down a minor third (etc.) Once you can hear intervals, it's as easy as the alphabet. I'm sure you know your alphabet when you see it.

So usually the second note, or third note I play is the melody note. It didn't used to be that way.

They all of your musical knowledge comes into play. How is the melody behaving. There are so many cliches that can help you figure out where you are in the key.

You'll use:
key knowledge
common chord progression knowledge
relative pitch

The more you know about music, the more your musical GPS will "just know"

Back to the question:


- Option 3: Somehow you looked at the whole piece of music and saw that the song "settled" on some other note that was different than the first note and you worked backward to find the degree of the first note.


THAT'S IT! In a roundabout way. If I hear the first three notes of the song "summertime", I can tell you without going to the piano, that the song is in a minor key, and that the first two pitches are "mi" and "do". How do I know this? Did I figure it out just now? No. I just know, because I know the song so well. I may have learned it by ear, or I may have learned it from sheet music. But now, that will help me learn other songs that use those pitches, such as "Poor Wayfaring Stranger" (check out Eva Cassidy's version, very cool)

Back to the question:


- Option 4: Somehow you link the melody notes to the underlying chord progression, though that part isn't crystal clear yet since the melody note at the beginning of a phrase is often different than the chord at the beginning of the phrase.


This is definitely an important part of it, as mentioned above. Check out "list-of-chords.com". I cover the most basic chord progressions with examples. Also, just start to memorize as many tunes as possible. Each tune you memorize will make every similar tune easier to play by ear. Certain tunes, such as "Blue Moon" that use the I vi ii V progression will get you the most bang for your buck, so you may want to start there. But just start memorizing your favorite tunes, and it won't take long.

What really helped me was singing the melody on solfeggio.


Be sure to check out my list of piano chords website.