# Key of a song with capo on the 4th fret

I have a song I'm playing on guitar and the original key is C# minor. If I play with a capo on the 4th fret, the chord shapes in the song are Am, C, G, Dm, F and E. So would this technically change the Key to A minor?

When you play an Am fingering with a capo on the 4th fret, the sounding chord is C#m and sound is what counts. When other people listen to your guitar and sing or play along with it, they don't need to know how you used a capo.

would this technically change the Key to A minor?

No. If there's another guitarist, you can explain as a technical detail that you're fingering the chords like in A minor, but with capo 4.

• Why is it that so many guitar sites would call a chord A# instead of the far more common Bb?
– Tim
Jan 6, 2020 at 13:11
• @Tim I did it to avoid the added complexity of the question "why are some notes flat and some are sharp" that's not relevant here. Jan 6, 2020 at 13:21
• Good idea! Still it elicited a comment!
– Tim
Jan 6, 2020 at 13:24
• It could have been written as "A#m / Bbm" or something, but still, the point was to just say that the sound raises one semitone higher when you use a capo on the first fret. Jan 6, 2020 at 13:25
• +1) The explanation with the pattern pictures (chord shapes) is clearer and shorter than all we can say in words. @ Tim: I just posted an answer also ignoring the flat note problem. When I started Guitar playing I preferred the #-keys (and A#m is logical to introduce here as OP ask for C#m) Jan 6, 2020 at 13:34

No, you are playing in C# min. The point of the capo is to allow you to use open string chord forms in any key rather than bar chords.

• Since the chord shapes are 'as if 'I was playing in the key of Am, but the capo is on the 4th fret, therefore the Key is C# min because: Am + 4 semitones = C# min. Am I thinking about this correctly??? Thanks in advance. The capo thing can get real confusing and all the capo cheat sheets online look different, so its hard to know what's the best logic to use to figure this stuff out.
– Kim
Jan 6, 2020 at 3:48
• Yes you are thinking correctly and it does get confusing.
– user50691
Jan 6, 2020 at 11:16
• How is it confusing? The capo is just like a sixth finger that is holding a barre for you. That shape you're playing is exactly like the Dm barre chord, slid down one half step to C#.
– Kaz
Jan 7, 2020 at 6:20
• Or an Amin moved up. Can you even play Dmin open a half step back? It can be confusing for beginners and I've seen orchestral charts written by professionals that screw it up.
– user50691
Jan 7, 2020 at 11:30

All those chords are diatonic to key Am - when there's no capo. Wherever the capo goes means you count up that many semitones. So if it was on the second fret, all the chords would be one whole tone higher. In this scenario, they'd be Bm D A Em G F♯, respectively.

However, you've gone up another tone, making two tones higher than original no capo chords. Now, they're C♯m E B F♯m A G♯. Putting the key into C♯m.

The chord shapes as quoted make it easy to change the key to whatever you want. They're basic chrds, and become dependant on where the capo is. That song, with capo on 4, will come out as in C♯m on a standard-tuned guitar.

The capo thing can get real confusing and all the capo cheat sheets online look different, so its hard to know what's the best logic to use to figure this stuff out.

The best logic to understand how it functions is:

1. to learn the chromatic scale
2. to learn the names of the strings
3. to understand what tones will sound when you play a certain chord pattern

The best is you write on a stripe of paper the chromatic scales on the neck along the frets:

e.g. referring to the A-string

1. A-A#-B-C-C#-D-D#-E-F-F#-G-G#-A (A = fret 0 or open string)
2. let's assume you know the string names from 6,5,4,3,2,1 = E,A,D,G,B,E
3. The chord of Am is built on the triad A,C,E: so we can use the open strings E,A and E (6,5,1)

Finger: String: Fret: Tone:

1-------- B--------1----> C (up 1 semitone)

2-------- D--------2----> E (up 2 semitones)

3-------- G--------2----> A (up 2 semitones)

and you play the finger pattern 123:

what happens if you push or press down a string?

by each fret higher you shorten the string and the tone is a semitone higher!

this explains why you have to put your fingers on the frets mentioned above to build this tones A,C,E on the strings G,B,D

what happens if you put the capo?

all strings are shortened and the chord is transposed up by each fret you move the capo:

also the A-minor chord (and any other chord you learn ... like C, G, Dm, F and E) will be transposed up a semitone by each fret.

so we get moving the a-minor chord with the capo (mind the chromatic scale A,A# B,C,C# ...

fret 1 => A#m

fret 2 => Bm

fret 3 => Cm

fret 4 => C#m

etc.

if you play the A-minor chord with capo you will transpose up this chord by each fret (+ a semi tone;

mind that you have to learn also the enharmonic names of flat notes (the black keys of the keyboard) that are equivalent to the sharps (#) that are described above.

Here's a quick and dirty rule that you can apply without thinking about it. (Though it's good to eventually get a real understanding.)

The open strings of a standard guitar are tuned to C major (and A minor).

Imagine the note C (or A) on the piano, count up 4 additional semi-tones, and you'll be on E (or C♯).

The guitar is now tuned to E major (and C# minor) with a capo on the 4th fret.

• 'The open strings ...tuned to C major...' How is that? Did you mean 'the open chords you used were...'? Some readers will be confused here!
– Tim
Jan 6, 2020 at 17:45
• @Tim, I did say "quick and dirty", "without thinking, and without "real understanding", so confusion isn't an option. What I meant is that all the strings match white keys on a piano, which form the C major scale. Jan 6, 2020 at 18:50
• By "Tuned to C major" what you mean is, it's analogous to a transposing woodwind/brass instrument "in C", in that C major chord shape will produce concert C major. Capo at 4th fret now makes your guitar "in E". Jan 7, 2020 at 18:42

I don't know what you mean by 'technically' changing the key?

You're playing chord shapes in A minor - THINKING in A minor - but on an instrument that has been shifted up by 4 semitones. So an Am chord shape produces a C♯m sound.

No technicalities, just that straightforward fact.

• I guess I should've asked, if someone asked me what Key was I playing in, how would I respond?
– Kim
Jan 7, 2020 at 6:12
• All they're interested in is what key the music SOUNDS in. Which seems to be C#minor. No-one cares what method you use to produce it. Jan 8, 2020 at 0:38

The method I use to determine the capoed key is based on which root chord form (C, D, E, A, F, G, etc.) in first position I'm using to play higher on the neck in the capoed position. I simply add 1/2 steps represented by the frets to the original chord fingering pattern to arrive at the newly adjusted key. In order to determine the scale fingering pattern for playing a melody, you can then use the CAGED fingering patterns, selecting the fingering pattern associated with the original uncapoed root chord, but I have to say I don't know any players that actually use a capo to play melody. Most melody players/ improvisers, simply determine the key and chose their own preferred fingering patterns to play along with. It's a simple concept made more confusing by the number of root position chords in the first position. The main thing to know is which root chord you start to count from.

• Aren't E and F the same 'root chord form'?
– Tim
Jan 6, 2020 at 21:04
• @Tim- I'm guessing you are referring to the barred form, which is the same idea as using a capo, whereas I was thinking of the other form on the first four strings, 1-1-2-3. Thank you for clarifying that. Jan 7, 2020 at 3:49