How Can I Tell What Key A Song Is In?, Kris said this was a popular question ..
Andrew Cockburn
Mar 13 2007, 08:56 PM
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Finding the Key of a Song

Ok, so you have a killer MP3 of some band you have downloaded that you want to Jam to, or you have an amazing tab that you want to develop ideas from, or maybe even a piece of music that you want to work with. Before you can do anything, you need to figure out the key that the song is in so that you can apply all of your knowledge about scales etc to figure out which notes to play. In this lesson we’ll try and figure out some ways to do this. There is no substitute for experience with this, and there isn’t always a failsafe formula, but a little knowledge can go a long way towards helping you with this. We’ll look at getting the key from Music, tablature, and also by ear, and by example.

Sheet Music

So lets take the easiest case first – you have some sheet music for the song you are interested in. I am calling this the easiest because in this case there is a failsafe formula you can use. Of course, if you don’t read music this may not seem easy to you … If there is any interest, maybe I will write a future series on music notation. If this isn’t of interest to you, just skip ahead to the next section on tablature.

If you read music, you probably already know about key signatures. The key signature is written as a group of symbols at the beginning of the piece of music, listing either a number of sharps ( # ) or flats ( b ). The sharps and flats are always listed in a particular order, which is determined by the Circle of Fifths, although that isn’t important for this exercise (note to self - write a Circle of Fifths lesson!)

Here are a couple of examples:

The key of C – no sharps or flats

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The key of E – four sharps

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The key of B flat – 2 flats

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Now, assuming you understand the notes on the staves above you can very quickly determine the key using the following simple rules. (If you don’t know the notes why are you looking at sheet music anyway?  )

1. If there are no sharps or flats the key is C.

2. If there are sharps, look at the stave line that the last sharp symbol is placed on, and go up 1 degree of the scale. In the example above, we have 4 sharps, F#, C#, G# and D# (again, these are derived using the circle of fifths). The last sharp is D# - one degree up from that is E. Another way to put this is that this sharp sign gives you the 7th of the scale. One up from that is the 8th, or root, giving you your key. So the example above is in the key of E just as we thought.

3. If there are flats, look at the stave line that the last symbol is on and go down 4 degrees in the scale, or to put it another way, the last flat sign gives you the 4th of the scale. In the example above we have Bb and Eb – 4 degrees down from Eb is Bb, which is the key (Eb-D-C-Bb in sequence). This rule isn’t particularly helpful if you are struggling to work out the key, and there is actually also an easier trick for flats that I prefer. This comes out of the circle of fifths and the fact that we are going backwards (I really need to write that circle of fifths lesson!), Don’t worry about the details for now but believe me when I say that each flat in a key signature is separated by 4 degrees, so you can look at the flat immediately before the last one which will give you the exact key signature. This doesn’t work for one flat, so you just need to remember that one flat is the key of F. In our example, the last but one flat was Bb, which is our key.

So, using the rules above and a sheet of music you can immediately deduce the key … apart from one subtlety. If you have read my lesson on relative minors, you will know that each major key has a related minor key. They are related by virtue of the fact that they share the same key signature. So you can narrow it down to 2 possibilities using the key signature, after that, you need to decide if it is major or minor – see later in the “by example” section.


So much for exact methods – it gets a little harder from now on. Guitar tabs are an informative guitar-friendly way of putting riffs down, but they generally don’t include as much information as sheet music. In particular they miss timing and key information, often relying on backing tracks and descriptions and analysis to support them – if you are lucky the description will give you the key. Also, a lot of tabs published in magazines include the key at the top of the tab. So if you have a tab without the key how do you tell what key it is in? Well at least you have the notes, which is a good start. One method is to write down all of the notes in a bar or two and compare them to scales that you know. If you can pick out 8 different notes you stand a good chance of figuring it out, if you only have two you might be stuck (in that case I suggest you listen to the backing track if there is one and use the “by example” method). If you pick out 8 notes and for instance they are A,B,C,D,E,F and G that gives you some strong clues. The first 2 options are the key of C and the key of A minor – probably the most likely possibilities. I worked this out by ordering the notes and comparing them to the notes in various major scales (its useful to have a reference somewhere for this, such as the Guitar Grimoire).

Other possibilities include the various modes of the C Major scale. In roughly diminishing order of likely hood these would be:

• A Aeolian (the same as the A minor above),
• F Lydian, G Mixolydian
• D Dorian, E Phrygian
• B Locrian

If you suspect modes are in use, experience helps you to figure this out, in particular, check out the chord that is being played as it will likely give you a clue to the mode – for instance Em or Em7 would point towards a Phrygian scale rather than a standard major.

Of course you may run into some very complex scales that aren’t easy to spot by looking at the notes, or even someone is just plain “cheating” in which the song is being played chromatically or without reference to a particular scale. Once again, knowing the backing chords will help you here.

By Ear

Some people are able to listen to a piece of music and instantly tell what key it is in. How do they do this? Well, there are two ways. The first is called perfect pitch. It refers to the ability to hear a note and instantly know what that note is. It is generally believed that some lucky people are born with this ability, but others argue that it is possible to acquire it through training. I am somewhere between the two schools of thought – I believe that a good ear can be trained to perfect pitch. Through experience I can usually get within a semitone of an E when tuning a guitar without a tuner, but not reliably enough to dispense with the tuner altogether!

In either case, you need a certain amount of musical experience to deduce the key even if you do have perfect pitch, and people who can do this will be unconsciously using the techniques I describe shortly in the “by example” section.

The second way I am going to call “by character” – I don’t know if there is an official name for this, but experienced musicians can usually tell from the selection of notes in a chord and the particular resonances in a piece of music exactly what chords are being played. This works best for guitar players listening to guitar pieces. For instance, a chord of C to me sounds very different to a chord of G, even when I don’t know what it is. It gets harder when the chords move away from open strings. This technique is definitely more based on experience than having perfect pitch. Once again, when you have the chords you would apply the techniques below to figure out the key. You can train yourself to get better at this by playing various chords and listening what they sound like and identifying the root notes.

By Example

This is the method that probably most of you will be using at least to start with, especially when trying to figure out the key of your guitar hero’s solo. The key to this (pun intended!) is to figure out what chords are being played. To do this, pick up your guitar and try to identify the root notes of the chords by playing notes up and down your E string until you find a match. Your chord listening training above will come in handy, because you are always looking for the root note of the chord, not one of the additional notes. By this I mean that for instance a chord of C major has the notes C,E and G in it. C is the root here. When you are trying to pick a C chord out of a piece of music you are listening to, you need to identify the C note, not either of the others or you will be off in the wrong direction!

For each chord you identify, you need to decide if it is in the Major or Minor family – again, there is no rule for this, you need to train your ear to understand the difference. A starting point is that major chords sound happy, and minor chords sound sad, but you need to try this for yourself with chords you know.

Now you have a list of chords, it gets even hazier. You next need to try and figure out what the tonic chord is. That’s a fancy way of saying the root chord or 1st of the scale. In music there is always a tension and movement between different chords in the song, such that when you get to the tonic or root chord, there is a feeling of resolution, or being back on home ground. Other chords lead you off in various tonal directions, but the end of the journey is almost always back to the tonic. The tonic may or may not be the first or last chord played, but there is usually a sense of completion when you get there. If you don’t know what I am talking about you need to train your ear some more to pick this up! In fact, most often, the chord a song ends on is the tonic which can be a good clue. But, if the songs ends with an uneasy feeling of something missing it could be because it isn’t ending on the tonic, so be careful!

When you have identified the tonic, be it major or minor, you are pretty much there – the rest of the chords may help to confirm it as there are usually families of chords played in a particular key that have root notes that match the scale in question. For example, the key of C/Am has the following characteristic chords:

C, Dm, Em F, G, Am, Bdim

These are the chords that make use of the notes in the scale they belong to. If you see that the chords in the piece you are working on include these, or variants of them, it is a good sign that you are in that key. However, these chords are really just a jumping off point, and don’t take account of the fact that there may be sudden key changes in the song, or the composer may just plain and simple ignore the rules and throw in some random chord because it sounds cool. As with all theory, this is just a framework to hang your creativity on, it isn’t a straitjacket that constrains you.

Well that’s about it. In all of this there is no substitute for experience and ear training, and no guarantees you got it right (you'll figure that out when your scales sound wrong against the piece in question), but practice a lot and soon you’ll wonder what all the fuss is about – can’t anyone tell its in that key?

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This post has been edited by Andrew Cockburn: Mar 28 2007, 01:04 AM

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Posts in this topic
- Andrew Cockburn   How Can I Tell What Key A Song Is In?   Mar 13 2007, 08:56 PM
- - mattacuk   Another fantatstic Lesson. I really wanted to know...   Apr 30 2007, 01:54 PM
|- - Igorrr   Great lesson, especially the info on the last # be...   May 7 2007, 10:00 PM
- - kevin-riff-after-riff   hey andrew, hmm, the music staff is in the wrong o...   May 7 2007, 10:51 PM
|- - Andrew Cockburn   QUOTE (kevin-riff-after-riff ...   May 7 2007, 10:57 PM
|- - Igorrr   Was in doubt (never really cared) and by randomly ...   May 7 2007, 10:59 PM
- - Xranthoius   Man, I cannot believe I read the whole thing, it k...   Nov 25 2007, 04:40 AM
- - shammy   yeah me too, I have read the whole lesson complete...   Dec 16 2007, 04:42 AM
- - Philippe   Thanks a lot for this explanation, but I'm sti...   Dec 25 2007, 08:49 AM
|- - Andrew Cockburn   Hi Philippe, Some very good questions there! ...   Dec 25 2007, 02:31 PM
|- - Philippe   Thanks for your answer!   Dec 25 2007, 05:29 PM
- - Slammer   I have a quick question... Sorry it may be a real...   Jan 12 2008, 01:48 AM
|- - Muris   Yeah,it IS in Key of C Slam. You don't have to...   Jan 12 2008, 01:56 AM
|- - FretDancer69   QUOTE (Muris @ Jan 11 2008, 06:56 PM) Yea...   Jan 17 2008, 03:32 AM
|- - Muris   QUOTE (FretDancer69 @ Jan 17 2008, 03:32 ...   Jan 17 2008, 04:01 AM
|- - FretDancer69   QUOTE (Muris @ Jan 16 2008, 09:01 PM) Wel...   Jan 17 2008, 04:11 AM
|- - Andrew Cockburn   Hey Fret, I sympathise with your question - its al...   Jan 17 2008, 01:34 PM
- - Slammer   Hey Thanks Alot Muris. That Really Helped me alo...   Jan 12 2008, 03:30 AM
|- - Muris   QUOTE (Slammer @ Jan 12 2008, 03:30 AM) H...   Jan 12 2008, 02:13 PM
- - benhowell   Great lesson Andrew, very well explained. -Ben   Jan 12 2008, 04:23 PM
|- - Andrew Cockburn   Thanks Ben   Jan 12 2008, 06:01 PM
- - FretDancer69   thanks andrew, i do listen to alot of music, almos...   Jan 17 2008, 09:29 PM
- - FretDancer69   Hey Andrew, i was re-reading this lesson again and...   Feb 4 2008, 06:05 AM
|- - DeepRoots   QUOTE (FretDancer69 @ Feb 4 2008, 05:05 A...   Feb 4 2008, 06:14 AM
|- - Andrew Cockburn   QUOTE (DeepRoots @ Feb 4 2008, 12:14 AM) ...   Feb 4 2008, 06:30 AM
|- - gudinho   Andrew, great article I never had this Music theor...   Apr 4 2008, 08:15 AM
|- - Andrew Cockburn   Sure - thats a good point - a lot of the time the ...   Apr 4 2008, 01:00 PM
- - -Zion-   hi Andrew. I have a question about finding the ke...   Jul 30 2008, 08:15 AM
- - wrk   Andrew can explain this maybe more clearly, but on...   Jul 30 2008, 09:07 AM
- - -Zion-   Hi wrk and thank you for your input So i have been...   Jul 30 2008, 09:47 AM
|- - wrk   QUOTE (-Zion- @ Jul 30 2008, 10...   Jul 30 2008, 10:09 AM
- - DeepRoots   You seem to have analysed it well enough Next id...   Jul 30 2008, 10:00 AM
- - -Zion-   QUOTE (DeepRoots @ Jul 30 2008, 11:00 AM)...   Jul 30 2008, 10:21 AM
|- - DeepRoots   QUOTE (-Zion- @ Jul 30 2008, 10...   Jul 30 2008, 10:39 AM
- - wrk   DR said everything ... Two approches were helpfu...   Jul 30 2008, 11:02 AM
- - -Zion-   thank you both.. i believe i still have some work ...   Jul 30 2008, 11:15 AM
|- - Andrew Cockburn   Um, hello? Guess I'm not needed around here an...   Jul 30 2008, 04:22 PM
- - kevvyg   Hi, on the subject of key signatures, I learned so...   Jan 27 2009, 02:12 PM
- - Fuebob   Hi mates Sorry for digging here I've got a ...   Mar 22 2016, 03:47 PM
|- - Andrew Cockburn   Hi Fuebob - You need to keep in mind the root no...   Mar 23 2016, 09:35 PM
|- - Fuebob   QUOTE (Andrew Cockburn @ Mar 23 2016, 09...   Mar 23 2016, 11:34 PM
|- - Todd Simpson   Great answer from ANDREW!!! Nice That...   Mar 24 2016, 12:38 AM
- - Andrew Cockburn   QUOTE (Fuebob @ Mar 23 2016, 06:34 PM) Ma...   Mar 24 2016, 02:50 AM

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