Key Signatures and How to Read Them

Jan 13, 2021
girl confused, trying to understand key signature with sharps, flats and naturals

By Marie Votapka


Since our last blog update broached the subject of music theory and the importance of knowing the notes, I thought I’d cover another aspect of music theory that I feel is commonly left out or under-taught. That topic is key signatures. Before I delve into all that, I want to define some key words, terms and symbols. 

Key: In music, the key is what note the song or piece is based around. From this, you will know what scale (series of 8 notes) the piece of written music includes by default. It is indicated by showing you a certain number of specific sharps and/or flats at the beginning of the song before the music starts. 

Sharp (#): This symbol (as much as I cringe to say it, the one that looks like a hashtag) indicates that a note should be played half a step higher than it is normally played. It is always placed on the staff line in front of (that is, to the left of) the note. The sharp symbol will sit on the line or space on the staff of the note that is intended to be played this way. 

This note is F sharp. The sharp symbol is on the same space where the note “F” is, so the sharp applies to the F. The letter designations for the lines and spaces never change. The sharps and flats merely modify that letter by half a step in either direction.  

Flat (b): This symbol looks kind of like a tiny lower case “b”. It tells you that a note should be played half a step lower than it is normally played. Like a sharp, it also sits to the left of the note it is attached to, and on the same line or space. Sometimes when you have a lot of accidentals in a measure, it can be confusing at first to distinguish which note gets the accidental. (An accidental is a sharp, a flat or a natural symbol in a measure.)

To help you remember where accidentals go, I refer you to the Queen:

Using the same concept, an F flat would look like this:

Natural: This symbol tells you that any sharps or flats you have seen (whether in the key signature, or only in that specific measure, either one) are cancelled in regards to a specific note. This only applies to the note on that exact line or space. As with any other accidental which appears in the measure and not in the key signature, as soon as that measure ends, all bets are off and the accidental is canceled and reverts to the default of whatever is given in the key signature. To give you a visual, here is an F natural:  

Tip: F natural is the same as F. If your teacher says "play an F" and you play a Low 2 on the D string, you have succeeded. If your teacher says, "Play an F natural" and you play a Low 2 on the D string, you have succeeded. The word "natural" just emphasizes that it is not sharp or flat.

So now, a little bit more about the way these things work together. When you place a sharp or a flat next to a note, it applies for the whole rest of the measure that it appears in. Once the end of the measure comes up, indicated by a bar line, the note is no longer sharp or flat, unless a new sharp or flat is written in. And here’s where I’m going to talk about the key signature. 

As you saw, the key signature shows you sharps or flats at the beginning of the song. When you see these, it means that those notes are sharp or flat for the entire duration of the song, UNLESS you see the “natural” symbol that I defined earlier. The natural symbol “cancels” the sharp or flat and tells you to play the note as you normally would in the note’s “natural” state - only until the end of the measure. What are the "natural" notes on the violin, viola, cello, bass, or any other instrument? Easy! It's the white notes on the piano! Also, the notes that are in the C Major scale.

So, the key signature is extremely important in being able to know right off the bat how you are going to be playing the music. If you ignore the symbols, you won’t know that you have to play some sharp or some flat, and the whole thing will end up sounding weird or off without you knowing why. Knowing how to read which notes are supposed to be sharp or flat before you start playing definitely gives you a leg up, but there is another piece of this that gives you even more information at a simple glance, if you know what you’re looking for. 

I'll give you an easy trick to immediately be able to tell which Major key you are looking at. Here we go. Get ready for the best key signature identification trick ever!

Easily Identify Key Signatures with Sharps

If you're looking at a piece of music and you see sharps in the key signature, go to the last sharp (the one furthest to the right). Figure out which note it is (i.e which line or space the sharp is sitting on). Let's say it's G, as in this image:

Go half a step up from G sharp, and what note is that? It's A. If half steps confuse you, we can just as easily say, "go one letter up" and you'll get the same result. And there you go, now you know the key - it's A major! Works for every major key when you see sharp symbols in the key signature


Easily Identify Key Signatures with Flats

If you see flats, that's different. But it's ok! This trick is even easier. Find the second to last flat (the second one from the right).

Figure out which note it is. And that's it! That's the key. So in the above picture, we would have E Flat Major.

Not only does this help you know what to practice (you should start off by warming up with the corresponding scale), it helps you to understand what notes you should expect to be playing throughout the piece.

Just Look At How Many Sharps or Flats There Are

Here's another piece of info. Based on the number of sharps that you see (or flats), without even looking to see which notes they are, you can tell what key the song is meant to be played in, and therefore which scale the song is based on!

The number of sharps and flats are always the same for each key signature. Meaning, if you see 1 sharp in a key signature all by itself, that sharp is always going to be F. Always. If you see 2 sharps in a key signature and nothing else, those 2 sharps will always be F sharp and C sharp. So once you start becoming familiar with what keys have what sharps, it's very consistent and easy for you to tell what is going on. To give you a visual on everything, here's a helpful chart:


Free Practice Tool

It might seem like a lot to process at first (it is, you’re not wrong), but lucky for you there’s another free online tool that can help you start absorbing this information. has a set of exercises to run you through the key signatures until you can recognize which one is which! Click here to go straight to the exercise and get started.  

When you get there, you’ll see something like this: 

Use the tools I've given bove and practice identifying the key signatures in flashcard style. It’ll let you keep guessing until you get it right before taking you to the next one. Run through the exercise as long as you want, and keep going back to it as many times as you need to start feeling confident about your ability to recognize the different keys. 

You can adjust the difficulty by limiting yourself to just a few at a time, and then expanding your flashcard pack until you improve.

If you’re feeling like you want to give yourself a challenge, or keep more track of your progress, there are various settings (I recommend using the “Challenge Mode” every now and then to give yourself a boost), plus a progress report that shows you how you’ve been doing. It’s a great way to accurately & objectively evaluate where you’re at without being too hard or too easy on yourself (although let's be real...most of us are too hard on ourselves). You can find the settings under the gear icon in the top right corner, and your progress report can be generated by clicking on the 3 dots next to the gear icon. Here's what your progress report screen should look like:

This can all be found under the "exercises" tab on the website. But, there are also more in-depth theory lessons that can help you to understand some more about key signatures. And this website does break it down for you in a way that's actually readable. Because, I'll be honest, things can get real complicated real fast sometimes, but it's just not necessary when all you're trying to learn is how these things work! For a more in depth look at key signatures, read all about them right here

Like I said, when you google "key signatures", you're likely to be bombarded with a lot of terminology that you then have to go and google...leading you to more terminology that you then have to go and google...and so on into a never-ending circle that'll wish you had never even googled it. That's not a great way to learn (obviously), because to understand something, you should be able to understand the words that it's being defined with! Just keep in mind everything is based on some simple concepts, and once you have those down, the more complicated things will start to click and will seem less complicated. 

The important thing is to work at grasping the basics first before you jump into the deep end and read too much that confuses you. If you ever feel like you understood something before and suddenly no longer understand it (trust me, been there), you just need to cut it back a bit.  As soon as you start to feel like you’re in over your head, pause and take a step back. Think about the last thing you understood the most. Go back to that and look it over again. Work on that some more and make sure you have a really solid grasp on it. You’ll likely find there was something about it you didn’t completely have down cold, which is why the new information caused you some confusion and made you feel like you didn’t get anything. We’ve all been through it! Just don’t give up. Stick to the things that make sense, and take it step by step. You have to walk before you can run. It can be frustrating for those of us who like to dive right in (*cue me raising my hand), but patience is important. Going all out too soon can make you feel like you want to stop, when you just needed to take a bit more time to understand the essentials first. 

Key signatures are certainly part of the essentials, and starting with the basics like understanding the symbols and how they work will lay some very important groundwork for your future learning and playing. You’ll find yourself less confused when looking at sheet music, your sight-reading will improve (because you’ll already have an idea of what notes to expect), and the concept of how music flows will start to come together for you the more you become familiar with the various keys, what they look like and how they sound. Plus, if you’re more into jamming with friends than reading sheet music, knowing the keys can help you here too! Just ask your friends what key they’re playing in and only play notes that belong to the scale that corresponds with that key! i.e if they’re playing in A major, only play notes from the A major scale (even better - the arpeggio) and you’ll fit right in. Stay tuned for more articles on this and let us know if you'd like to hear more about this.

All in all, whatever your musical goals are, you should have this basic knowledge under your belt. I’m not going to lie, for me personally this had been omitted for a large part of my musical education and the struggle was not worth it. Take the time to grasp these ideas as early on as you can (whether you find it boring or not) and you’ll thank yourself (and maybe me, for encouraging you) later. And if it’s not early on for you and you feel like this is something you should know already, don’t be embarrassed. I did not truly grasp these ideas until a good way into my learning. My mistake was just never asking the questions I had, because I felt like I should know it already...but the truth is, if you don’t know it, you’re better off asking! No good teacher will judge you for what you don’t know. That’s what we’re here to do - to help you know what you don’t know!

Keep up your studies, your practicing and your exercises and all of your hard work will pay off. I promise. 

Best of luck to you.