Music theory: it kinda stinks, right? All those harmonic scales and key signatures and the circle of fifths… It’s enough to make a grown man cry. Or at least, to make my younger self wish wholeheartedly that I could quit piano lessons and go home to play my Super Nintendo.

My History with Music Theory

Being honest, the music theory classes my parents made me go to left a very bad taste in my mouth. Rather than learning to appreciate music more, those lessons felt like a complicated, frustrating waste of time. Even after I learned chord-based piano techniques and started actually enjoying the piano, I still found music theory stressful.

But that changed when I broke the most important parts of music theory down to its simplest form. It opened the floodgates for my appreciation of all different aspects of music: listening, playing, improvising, and more. Being able to communicate these essentials to my piano students has been a game-changer for them, too!

Many of my thousands of students didn’t really get music theory at all, either because they never understood it or they never were exposed to it. But what I’m going to explain in this post is accessible to anyone who wants to learn the most important music theory concepts for piano (and they apply to many other instruments as well).

This doesn’t have to be intimidating.

The Plan

Here’s how I’m going to tackle this broad topic of music theory and teach you the most important basics in just one post:

In Part 1, we’re going to answer the question, “what is music theory?”

In Part 2, we’ll talk about sounds and notes.

Part 3 will be for all things chord-related.

Part 4 is where we’ll learn about chord progressions and songs.

And Part 5 (whew!) will be all about scales and keys. Still with me?

Part 1: What is Music Theory

In its simplest form, music theory is like a language: the language of music. It’s a way to describe and understand not just how music works, but why.

If I teach you to mimic me playing a specific sequence of chords, then all you will know how to play is that sequence. I can even physically place your fingers on the notes and show you exactly how I interpret the chords in the sequence. But what good does that do you if you have no idea why?

If I then told you: “play the 1-5-6-4 progression in the key of major, making the 6 a minor 7th and inverting the 4 and 5”… would you know what to do with that? Or does it sound like a different language?

Well, that is a different language! It’s the language of music. And if you understand what I mean, you can play what I told you. It could become second nature for you with a bit of practice.

On the other hand, you’d be completely lost if you didn’t understand that language. And even if I taught you to parrot the result on your piano or keyboard, you wouldn’t understand how to apply it elsewhere.

A Trip to France

It’s like if we took a trip to France together. Imagine we’re at a beautiful cafe with a view of the Eiffel Tower. You notice a local at a table nearby, and you want to start a conversation. The only problem? You don’t speak a word of French.

I do speak some French, so I give you a line to say. You ace that line, and the person responds to you… in French. You’re now completely reliant on me to translate and tell you what to say. Because I’m not teaching you French, I’m just feeding you lines. It might work for a little while. But you can never have a meaningful conversation on your own that way.

What if you learn French before our trip? That completely changes the game. Now you can speak to that person in the cafe for as long as you want. You can relate to them, you can joke around with them. You can even start planning the rest of your lives together, if that’s how it goes. 😉

But the ability to communicate in the language is key. That amazing second scenario is how I picture music theory: the key to meaningful experiences and really connecting.

You start learning a language with some simple building blocks of letters and sounds. It’s time to talk about the building blocks of music theory.

Part 2: Building Blocks

The most basic building block for music theory (and for learning any instrument)? Notes. 

What a Note Is

A note is a sound that vibrates at a consistent rate, so that it sounds the same the whole time you hear it. That sounds more confusing than it actually is, so bear with me for a moment.

See, all sounds are vibrations. If we could see these vibrations, they would be shaped like waves. While you can’t see them travel through the air,  you hear them when they vibrate your eardrums. That sends signals to your brain which it interprets as sound. That’s what we’re talking about when we discuss what sound really is.

If something vibrates extremely fast, we hear that as a high-pitched sound. On the other hand, a slow vibration means lower, deeper sounds.

I demonstrated this in the video embedded earlier in this post. (I even broke out a ukulele and did a drawing by hand, so check that out if you want to see exactly how this works!) No matter what instrument you play, vibrations are what make up each note.

Notes on the Piano

On a piano, all the sounds are in order from lowest on the left to highest on the right. That’s why even a little kid can make a cool sliding sound effect by running their hand back and forth in order across the keys.

The piano is built so that each note vibrates slightly faster, the farther to the right that you play. Like I said earlier, faster vibrations mean higher sounds! So that’s what we get as we move “up” the keys: higher notes.

Speaking of notes, here’s one: a random vibration isn’t the same as a note in music, even though it might produce a sound. In the language of music theory, it’s safe to assume that a normal note will be one that vibrates consistently at the same rate, producing one consistent sound.

How Many Notes are There in Music?

If you understand that notes are just consistent vibrations causing sound waves, you might think there is a possibly infinite number of notes that can exist. That might be true in a theoretical sense, but it’s not true on instruments that have a limited range they can vibrate! So don’t worry, the actual number of notes is pretty limited for our purposes.

Take a look at a piano or keyboard (or a picture of one). There can only be up to 88 keys. Does this mean there are 88 notes that can possibly exist in music? Well… yes and no.

Math in Music

It turns out, if a sound vibrates exactly twice as slow or fast as another sound, your brain can tell. And it interprets it as basically the same sound, just higher or lower! That means that your brain can tell the difference between truly different notes, and notes that are the same except for their higher or lower pitch. Pretty cool, right?

If you play an A note on your piano or keyboard, and then a different A note in a lower or higher set of notes, they all sound related. Even though you can tell the difference, there is clearly a connection. The connection is one that you hear but can’t see.

Every time you play a lower version of the same note, you are causing a vibration that is half as fast at the higher version. And every time you play a higher version, you’re causing a vibration that’s twice as fast. So it’s basic math: moving lower halves the vibration, moving higher doubles it.

A Bit More On Sound Vibrations

For trivia’s sake (because I promise you do not need to remember this information), just how fast does a note vibrate?

For our example of playing A, the center A note on your piano vibrates at 440 times per second, or 440 hertz (hz). The next A note to the right is vibrating twice as fast: 880 times per second. And it keeps doubling, faster and faster to the right and vice versa.

These numbers aren’t really important unless you’re a professional instrument manufacturer or tuner, or maybe a sound technician. But for the record, each note has its own rate of vibration, and in theory you could call any consistent rate of vibration a note. We could have 441 hz, 442 hz, 442.5 hz, 442.6 hz, and so on… and yes it could kind of converge on infinity.

Why Not ALL the Sounds and Notes?

Here’s the thing: not all of the sounds that the infinite range of vibrations makes are nice to listen to. And most of them don’t sound good together. That’s actually a good thing: it literally narrows our playing field. 😉

Some very smart people figured out that there are certain notes that do sound good and can work together. They are spaced out evenly across that range of possible notes, and it turns out there are 12 of them! That’s the basis for most of music theory today: the 12 notes that form the Western music scale.

What About Non-Western Music?

I’ll be the first to admit that I am not very familiar with non-Western music. But it’s important to point out here that there are some other sets of notes that do work in other styles of music. If you’re interested in more diverse sounds than you might be familiar with from the Western canon, it’s a fascinating topic and worth checking out!

The 12-Note System

Once people identified and started working with 12 specific notes, they needed a way to describe them! The most popular names for these notes use letters from the alphabet, like the A note in my example about vibrations.

For reasons we’ll get into later, the notes do not start at A. Instead, they go like this:

C, C sharp, D, D sharp, E, F, F sharp, G, G sharp, A, A sharp, B.

An easier way of writing it is:

C, C#, D, D#, E, F, F#, G, G#, A, A#, B.

That’s 12 notes, and they are all you really need to memorize on your keyboard or piano, because they repeat the whole way across!

Tones and Semitones

There are a few important things you need to know about these notes. From each note to the next is called a semitone or a half step. So If I tell you to play one semitone up or one half step up from A, that’s A sharp (A#). One semitone or half step down from A is G sharp (G#), etc.

The distance between two notes is a tone, or a whole step. So from G to A is a tone or whole step. From G to B is two tones, or two whole steps.

These terms semitone/half step and tone/whole step are just ways of describing how far different notes are from each other in placement and sound. Don’t get bogged down here: just think of them as measuring sticks. 😉

Octaves

What about octaves? You’ll hear this term a lot when learning piano! All it means is that you are switching from one set of 12 notes to another.

So if you’re playing a C note at the center of your keys and you move to the next C note 12 keys to the right, you are moving up one octave. If you moved to the C note after that, you’ve moved two total octaves. Whichever direction you move, if you are playing the same note(s) in a different section of your keyboard you are just playing in a different octave.

Identifying Octaves on Your Piano

Like I said earlier, all the keys on your piano are just sets of 12 notes that repeat. Depending on whether you have a full-sized keyboard or not, you might have fewer sets.

On a full 88-key piano or keyboard, you will have 7 total octaves, plus a few keys to spare on either side. Let’s take a look at any one of those octaves. Where do they start and end?

Each set starts on a C note, which will always be the white note to the left of a pair of black notes (not the one to the left of any three black notes: that’s an F note).

White and Black Notes

If you’ve gone through any of my resources or watched any other videos from me, you’ve probably heard me say this already: there is no big, scary difference between the black and white keys. They are colored and arranged differently to make things easier, not harder! If all the notes looked the same, playing piano would be way more confusing.

If we just look at the white notes for now, they go like this from left to right: C, D, E, F, G, A, B.

Those are the seven white notes. They start over from C once you get to B. It’s a little weird, I know, but I didn’t make the rules!

Meanwhile, the black notes get their name from the keys they are next to. So black note to the right of C is C sharp (C#), the black note to the right of D is D sharp (D#), and so on.

We can also identify the black notes by which keys they are to the left of. In that case, we call them flats instead of sharps. So the black note to the left of D is D flat (D♭), the black note to the left of E is E flat (E♭), and so on.

Another way of understanding the white and black notes and sharps/flats is that the black keys are one semitone or half step up or down from the white key they get their name from.

Notes vs. Keys

You may have noticed that I use the word “note” and “key” pretty interchangeably when I’m talking about the piano. Technically speaking, the physical objects you press when you play piano are called keys! And the sounds that result are called the notes. But on piano, you can usually call them either one.

This does not happen on other instruments (except maybe the accordion), because the mechanics of playing are different. Ukuleles and guitars use strings, you cover and uncover holes to play wind instruments, etc.

Later on we will talk about songs being in a certain key, or “playing in a key,” which has a very different meaning than what we’ve discussed so far. So I just want to make sure I mention this now: calling what you press on a piano a key or a note is just fine.

Part 3: Chords

Now that you understand the building blocks of music, notes, we can move on to chords. But we’ll never really get away from notes, because (simply put) chords are really just sets of multiple notes played at the same time!

There are about 27 different categories of chords – yikes – but you will never need to use most of them. In fact, there are only two simple types of chords that you need to be completely familiar with, plus a few variant types that are mostly pretty easy as well.

Unlike most piano teachers, I will never make you memorize numerous individual chords or ask you to play chords note-by-note from memory. That’s just not necessary with my approach. Allow me to introduce you to…

Major Chords

The most common type of chord is the major chord. They sound pretty happy and uplifting, and they are so, so simple to play.

All you have to do to play a major chord is use this formula: 4-3. Starting at the note the chord is named after, you just have to place your next two fingers 4 notes and 3 notes away, respectively.

Let’s look at an example. For D major chord (D), you start with a D note. Put your right thumb on a D note, then count 4 keys to the right (make sure you include black keys, they all count). Put your next finger on that 4th note, then count 3 more notes to the right. Put your third finger there. 

Now you have three fingers on three notes, the first one being D and the others found by using the formula. At this stage, you don’t even need to care what those other two notes are. If you press those three notes, you’ve play a D major chord!

This works for literally any major chord. If you place your first finger on the note the chord is named for, and place your other fingers using the 4-3 formula, you’re golden. It’s really that simple.

Minor Chords

Minor chords are the second most common chord you will run into on your music journey. They sound a bit sadder or moodier than major chords. But they’re just as easy to play!

The formula for minor chords is 3-4, so it’s just a reversal of the major chord formula.

For example, to play a C minor chord (Cm): place your thumb on the C note. Count to the right by 3 and place your second finger there. Count to the right by 4 more notes and place your third finger there. Press all three notes, and you’ve played a C minor (Cm) chord!

Again, this works with any minor chord. As long as you understand that 3-4 formula, you never have to individually memorize minor chords.

What About Flat and Sharp Chords?

Sometimes people who already know and use these major and minor chord formulas get a little freaked out when they see something like an F# or E♭m chord. That just means they’ve forgotten about the black keys and how they work. It’s really not that complicated!

If you see a flat or sharp major chord (such as F#, D♭, etc), you still can use the major chord formula.

If you see a flat or sharp minor chord (such as F#m, D♭m, etc), you still can use the minor chord formula.

The only difference to remember is that flats and sharps are always black keys, so your first finger of the chord is going to start on the black key the chord is named after. You still count and place the other fingers the exact same way, with the exact same formulas.

Part 4: Chord Progressions

Now that you know the most important chord types, what on earth can we do with those chords? Play them, of course!

If you play chords in a pattern or sequence, that’s called a chord progression. And that’s what most modern music is based on: chord progressions. If you’re learning with my resources, chord progressions are how you get to play real songs pretty early in your piano-learning process.

Here’s an example of a chord progression: Em, C, G, D. On your device’s screen that just looks like a list of letters… until you understand chord-based playing. If you can play these chords using the formulas we talked about in Part 3, you can play this chord progression! And if you do, you might notice that it sounds familiar.

That’s because this progression is from “All of Me” by John Legend. It’s what you would play for the introduction and all the verses in the song. That progression tells you what you need to know for almost half of the song! There are a few slightly different progressions for other sections like the chorus and bridge, but they’re basically as simple as the first one.

Almost all modern music (and a whole lot of golden oldies) is like that. Understanding chords and chord progressions unlocks the door to literally thousands of songs. If you know how to play major and minor chords, you can play all kinds of songs with just a bit of practice and patience.

Does Any Combination of Chords Work?

You may be asking, does any combination of chords work if you want to write a song? Can any chord progression work? Could someone pick a few chords randomly and combine them into a song that sounds good?

Sorry to disappoint, but no. There are reasons why certain chord progressions work and sound good. Those reasons are a part of music theory, which is why we’re talking about it here! And that brings us to a new topic.

Part 5: Scales and Keys

Understanding scales and keys will help you understand what chords work well together. But for some reason, scales and keys can scare even people with years of lesson – including me at one point. Even many long-time musicians seem to struggle with this, but that’s why I’m here: to demystify the topic.

The Key of the Song

Every song is “in” a “key,” which probably is a phrase you’ve heard before. Let’s look at some examples.

  • “Imagine” by John Lennon is in the of C
  • “Bohemian Rhapsody” by Queen is in the key of B♭m
  • “Wonderwall” by Oasis is in the key of F#m

But what the heck does that even mean?

In its simplest form, the key of a song tells us three useful and important things about that song:

  1. What seven notes will work best in the song (hint: also known as a scale)
  2. What chords could be in the song
  3. What the “home chord” is for the song

We’re going to take a look at each of these three important pieces of information; how we see them in the key of the song, and how we use that info to our advantage.

Finding Scale from Key

If you know the key a song is in, you can determine what seven notes can be used in that song. And you don’t have to memorize them all, because there are formulas for scales as well as chords! So let’s take a look at how that works.

Major Scales

If the key of the song is major, then you’re going to use a major scale formula. Here it is: 2-2-1-2-2-2-1.

The way we use this formula is relatively simple. Start at the note indicated by the key of the song. For example, “Imagine” by John Lennon is in the key of C. So to find the scale for “Imagine”:

Start at the C note and count using the formula 2-2-1-2-2-2-1.

  • Find the note that is 2 to the right of C (D).
  • Find the note that is 2 to the right of D (E).
  • Find the note that is 1 to the right of E (F).
  • Find the note that is 2 to the right of F (G).
  • Find the note that is 2 to the right of G (A).
  • Find the note that is 2 to the right of A (B).
  • Find the note that is 1 to the right of B, which brings us right back to C!

Each note that you’ve found in this process is one of the notes for the major scale of C: C, D, E, F, G, A, B, C. 

We can do the same thing for any song in a major key. And as you start trying this formula out, you will observe that certain key’s scales have some notes more than others. And some have more black notes than others. You don’t have to memorize this information, you just need to be able to find it when you need it, using the correct formula.

What Chords in a Major Key?

Not only can use use the key of a song to find its scale, we can use that same scale to figure out what chords are in that key! We start by assigning a number to each note in the scale.

Let’s use our example of “Imagine” again, in the key of C major. We use the major scale formula to determine that the notes in the C major scale are: C, D, E, F, G, A, B. Awesome. Let’s number those notes 1, 2, 3, 4, 5, 6, and 7.

The notes numbered 1, 4, and 5 from the scale (in this example C, F, and G) will tell you what major chords could work in the song. 

The notes numbered 2, 3, and 6 from the scale (in this example D, E, and A) will tell you what minor chords could work in the song. 

So not only does the key tell you what chords might be in the song, there’s only six possibilities. Three are major and three are minor. If you’re near a keyboard or piano and want to test this out, go for it! You’ll hear that the C, F, G, Dm, Em, and Am chords all sound good together. And that’s because we found them using the key of C and its corresponding scale.

An Example With a Popular Progression

Have you heard of the 4-chord song? It’s pretty famous these days, but check it out here if you haven’t already.

The four-chord progression is just a 1, 5, 6, 4 progression played in any key. Thousands and thousands of popular songs use that exact chord progression, and I tend to teach with it in the key of C, but it works in other keys.

Let’s take that exact same chord progression and try it in the key of A major, just to make sure you’re clear on how it’s done.

So if we start with the key of A and use the 2-2-1-2-2-2-1 formula, we find these notes in the A major scale: A, B, C#, D, E, F#, G.  Great. Now we number those notes from 1 to 7.

  • Chords 1, 4, and 5 are A, D, and E.
  • Chords 2, 3, and 6 are Bm, C#m, and F#m.
  • That means to play the four-chord progression (which is 1, 5, 6, 4) in the key of A major, you will play A, E, F#m, and D.

Changing the Game

By using this number system, you can find a chord progression you like or want to use, and transcend the original key it’s in. You never have to be stuck in one key again!

Before I really understood all this, I was playing on my church music team and getting by alright. But the band leader would ask me things like, “Hey Jacques, did you go back to the 1 there? Were you playing the 5 there and then the 6? Did you go to a 2 there?”

For the longest time I just had to fake it, because I wasn’t quite sure what he meant. But now I understand: he knew that regardless of key there were six possible chords that might be within the song, three major and three minor. And he knew that depending on key certain chords were very likely or unlikely. Now that I understand this too, everything is a lot easier.

Home Chords

Not only does the key of the song determine the scale and the chords within the song, it tells us what chord is most likely to start and end the song. That’s called the “home chord.” The home chord feels natural and comfortable when you play it, because it corresponds directly to the key of the song.

I don’t know about you, but when I’m at home I feel comfortable and safe. I love leaving on adventures, but it’s always a good feeling to come home. 🙂 And that’s what it’s like when you’re playing a song. Playing notes and chords that are farther from the home chord keep things interesting, then coming back to that home chord rounds everything out. Make sure you watch the example I give in my video, since this is a lot easier to hear than explain. 

Let’s say you’re playing a song in C major. Most songs in that key will start with… a C major chord. And that is the home chord! So if you’re playing in the key of C major, the farther you get away from that chord, the more the tension and emotion builds. The closer you get back to it, more complete or resolved the progression feels.

Using Home Chords to Determine Key

Most songs begin and end on their home chord, so if you’ve been wondering how to figure out what key a song is in, this is the right place. 

Here’s what you need to do to find the key of a song:

  1. Check the final chord of the song. That is likely the same as the key of the song.
  2. Check the first chord of the song. Does that match the final chord? That confirms that these chords are likely the same as the key of the song.
  3. If you’re still not sure, take a look at the other chords in the song. Working your way backwards, you can figure out what notes are in the scale for that song. That will also tell you what key it’s in for sure. (Note: Most of the time you will not need to do this step.)

Question Time

Wow! You’ve made it this far, and we’ve covered a lot of ground. You may have some questions. Not to worry! I like questions. 😉 Let’s take a look at some that might have come up in your mind.

What About the Missing Chord?

“If we can have seven notes in the key of a song, why wouldn’t there be seven chords as well?”

Aha, so you were paying attention! This is a really good question. Why didn’t we use the seventh note of the scale to find one more chord? The answer is that the extra chord almost never sounds good in combination with the others. It will not fit in with the rest of the scale, and for that reason I’m comfortable telling you, it’s better to ignore it. Think of it as a rogue chord and don’t worry about using it.

That said, if you’re still feeling curious: that chord is called a diminished chord, because it will use a different formula (3-3). The notes in it are closer together and rarely sound good, so you’ll rarely need it, if ever.

Can a Song be in a Minor Key?

“The examples in this post focused on major key songs. Can a song be in a minor key?”

Absolutely! Some very popular songs are in minor keys. You can identify them the same way that you would identify songs in a major key (checking the last and first chords, and working backwards if you need to).

The only difference is that you would need to use a slightly different scale formula for minor key songs. Rather than learn another formula though, I can show you an easier way.

Relative Majors and Minors

There’s this concept called relative majors and minors. It means that every minor key has a major key that’s related to it. And every major key has a minor key that’s related to it. If you know either one, you can find the other.

How to find a relative major from a minor key? Just move your notes by three to the right. 

You do the opposite to find a relative minor key from a major key. Just move your notes by three to the left.

For example, what if you’re playing in the key of Am (probably the most common minor key)? If you want to find its relative major key, all you have to do is move everything to the right by three notes. So that takes you to the key of C major. The scale and the corresponding chords for C major, you now can move back over into the relative minor key of Am if you need to. The only exception is that the home chord will not change. 

If you haven’t already, I recommend you watch my video example here.

Can a Song Have More Than One Key?

“Jacques, does a song have to stay in one key the whole time?”

Songs do not have to stay in one key. When they change keys, it’s called (no surprise here!) a key change.

Even though songs can change key, most don’t. And when a song does have a key change, it usually only happens once. A lot of songwriters find it gimmicky to write their songs with key changes. 

That said, some huge, international hits have key changes. Here’s just a few:

  • Whitney Houston’s “I Wanna Dance with Somebody” (as well as so many other Whitney songs!)
  • Michael Jackson’s “Man in the Mirror”
  • Celine Dion’s “My Heart Will Go On”
  • Lady Gaga’s “Perfect”
  • The Beach Boys’ “Wouldn’t It Be Nice”

I invite you to listen to some of these tunes and see if you can hear the key change. You can even take a look at the chord notation and see where it changes.

The important thing to remember about changing keys in a song is that when the key changes, so does the scale, so do the six chords for that key, and so does the home chord.

Why Do Black Keys Have Two Names?

“Seriously, why do we have two names for each black note?”

I completely understand why this feels frustrating: why can’t black keys be just flats or just sharps? Why do they need to be called both?

This is where we really get into the weeds, so feel free to skip this section! Not understanding the “why” for this is not going to have a negative effect on your playing.

Alright, so let’s say we’re playing in the key of C major. We have the notes in the scale: C, D, E, F, G, A, B. Seven notes altogether, right? The important thing to understand is that for every note, for every scale, the note should always begin with one of those seven letters.

Let’s look at the D major scale as an example. The notes in that scale are D, E, F♯, G, A, B, and C♯. This works better than saying D, E, G♭, G, and so on. If each scale has one letter represented per chord, 

What about the key of F? If you play F, G, A, A#… No, we don’t want to say A twice. So instead of saying A#, we say Bb and continue onward.

Depending on which key you’re in, the key (no pun intended) is to make sure that of the seven notes, we’re using all seven of those letters one time each. No less, no more. I don’t make the rules, folks: music snobs say this is how it is, and it’s not worth too much of your time unless you find this kind of thing interesting.

What About Accidentals?

“You said there are only seven notes per scale, so why does this song have more than seven?”

It wouldn’t be a rule if there weren’t exceptions! Sometimes songwriters create songs that have notes that don’t technically “fit” into their key. Those notes are called accidentals, even though they are usually added in very much on purpose. They usually are for accent, not to take over the whole song.

Sometimes a song might even have chords that aren’t technically correct for the key it’s in. And guess what, it’s not that big of a deal! This happens in the creative world: people making music don’t always follow the rules perfectly. So remember, you can’t blame me if you see a song that doesn’t fit my explanation of what “should” be in it. 😉

Wrapping Up

You made it! That’s a wrap for now. There are a lot of additional interesting topics that we could get into, but they’ll have to keep for another day.

If you apply even half of what you’ve learned from this post, you will have unlocked so much practical knowledge of music theory. And if you want to know how to put that knowledge to good use, I’ve got a free workbook for you. Over 200,000 people have downloaded it so far, and the information inside is a great companion for what we’ve already been learning here today. Music theory doesn’t have to be scary, and neither does piano!