Liam Ward
- May 9, 2023
- 4 min read

What Key Harmonica for the Blues?

Updated: Mar 7

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The harmonica is a versatile instrument but it is perhaps most closely associated with the blues. Blues (diatonic) harmonicas come in many keys - so which keys do you need in order to play blues on the harmonica?

TOP TIP: Types of harmonica

There are other types of harmonica available. Check out my guide to the 3 most common types of harmonica.

Firstly, blues can be played in any key. So if you are playing solo (completely unaccompanied) then you can use any key you like. However, blues bands tend to play in some keys a lot, and others very rarely, so if you want to play at a jam or with a backing track you will need to know which harmonica to pick up.

TOP TIP: Pro blues jam tracks

Check out my professional blues backing tracks!

Which Key Harmonica Should I Use for Blues?

To make things easy for you, I'm going to tell you the most common keys for blues. But I'll also teach you how to work out what key you need and I'll provide a full reference chart too, so that you can keep learning.

C harmonica

Almost all harmonica players start on a C harmonica. This is a good place to start, because most educational resources assume you're using a C harmonica. Using a key of C harmonica will allow you to play in the key of G (assuming you're playing in 2nd position - the most common way to play blues).

TOP TIP: Understanding 2nd position

Check out the Positions Guide for more information.

There are 12 keys in music, so there are 12 keys of harmonica, but some of these keys are very rarely used. The most popular keys for blues are the keys guitarists like to play in. I recommend six keys (seven if you include C). So what are they?

A harmonica

The A harmonica is a lovely deep and rich key. It's very popular and has a great range of notes. You'll hear lots of classic blues harmonica on A harp.

The A harmonica will let you play in the key of E in 2nd position.

D harmonica

This is a higher-pitch harmonica. It will respond quickly and cut through the band. It has a lovely raspy tone and is again very popular.

The D harmonica will let you play in the key of A in 2nd position.

G harmonica

The key of G harmonica is very low, with a big and rich tone. It's great for rhythmic playing and gives you a lovely warm sound.

The G harmonica will let you play in the key of D in 2nd position.

F harmonica

The F harmonica is very high. It may even sound a bit shrill to your ears, especially when played at home. However, in a band context it really helps you to shine through and float over the top of the music, rather than getting lost in the midst of the lower instruments around you.

The F harmonica will let you play in the key of C in 2nd position.

Bb harmonica

The Bb harmonica is a really sweet key. It's a personal favourite of mine because it's not too high but not too low. You get a lovely sound over the full range of the instrument, and most techniques will fit well on it.

The Bb harmonica will let you play in the key of F in 2nd position.

Eb harmonica

Finally, the Eb harmonica is relatively high - between the keys of D and F. It's a very useful key to play with brass players, so make sure you have one if you're going to be doing so.

The Eb harmonica will let you play in the key of Bb in 2nd position.

TOP TIP: Free blues tabs

I have 100's of free tabs on my website - visit the Free Tabs page for more.

How do you remember the keys?

To work out which key you are playing in, you can simply count up five letters from the key of the harmonica. For example C-D-E-F-G. So a C harmonica in 2nd position plays in G. If you count beyond G, start at A again. For example D-E-F-G-A. So a D harmonica in 2nd position plays in A.

This will work for all keys except B and Bb. The B harmonica in 2nd position is F#, and they Bb harmonica in 2nd position is F.

Full 2nd position chart

To save you having to remember all of this, I've put together a simple chart to show you the keys of the harmonica related to the keys of the song.

Chart showing harmonica 2nd position key — Harmonica 2nd position key chart

TOP TIP: Understanding 2nd position

Check out the Positions Guide for more information.

Hearing the key of a song

Your harmonica case should be arranged so you can easily access the keys you need. I use glow-in-the-dark stickers on the end of my harps and keep them in order of keys (from G up to F#) which works well for you, but you'll find a way which works for you.

If you're at a jam and you are not told the key, take a C harp and try the 2 draw note very gently so it doesn't interfere with the music. Cover an ear to help you hear the note resonate. If it feels like it fits really well, you may have the right harp. If not, try an A harp, and keep going through the keys mentioned above until you've got the right one. It will almost certainly be one of those keys because they are the most popular.

TOP TIP: Finding the song key

Check out How to Work Out a Song Key for a detailed guide.