All About Accidentals In Music Notation

What are accidentals in music?  Sometimes when we play a piece from sheet music, we come across a little musical symbol in front of a single note.
It will always be to the left-hand side of the note-head, and might look like this:

    • # (or ##)
    • b (or bb)
    • ?

We call these accidentals.

You may already have come across some of these signs in a key signature. But these are extra instructions, relevant only to the measure (bar) in which they appear.

What is an Accidental in Music?

Accidentals are more than just a folk-rock band.  In music theory and sheet music, accidentals instruct you to make a change to the note immediately next to it. They also apply to any other identical note in the same bar.

So if an accidental is in front of the note B, it changes all the other Bs in the measure too.

How Are Accidentals Written – And What Do They Mean?

Like all elements of music theory, we have standard ways of writing accidentals.  And accidentals work the same in melodies or chords.

accidentals in music notation

Accidentals are sharps, flats, and naturals that have been added only to a note or bar of music.


A flat is indicated by a b sign in front of a note.
It means we need to lower the note by a half-step (more on half and whole steps below). Our finger moves down one fret towards the tuning keys of the guitar.


A sharp is indicated by a # sign in front of a note.
It means we need to raise the note by a half-step. Our finger moves up a fret towards the body of the guitar.

Double Accidentals

We don’t often come across double accidentals in music. If we do, we just do the job twice.

  • A double sharp (##) means we move up two frets instead of one
  • A double flat (bb) means we move down two frets instead of one

So a double accidental changes the note by a complete whole-tone (more on this below). When we play it, it sounds like the next note up (or down) in the scale.

Which is strange, because wouldn’t we then expect it to have an entirely different note name?

Well, yes.  But standard rules in music theory prevent us from renaming that note. The use of the original note name keeps the special relationship of notes in a scale correct.

But What If We Want to Cancel the Accidental?

There are two ways to undo an accidental sharp or flat.

The Bar Line

The bar line cancels out any accidentals. So if we want a flattened note to be flat in the next measure as well, we have to use another accidental.

The Natural Sign in Music Notation

A natural sign cancels previous accidentals. It’s indicated by an ?in front of a note.  Sometimes, this sign is also called a kite, because it resembles one.

The natural sign (kite) cancels the sharp or flat of a note until the barline.

We use this symbol to cancel an accidental before the end of the bar.

For example, a B flat will revert to normal (B natural) if there is a natural sign in front of it.

Any other identical notes in that measure also then revert to their original status.

And the natural sign is also used to cancel out a flat or sharp in a key signature, and again only lasts for one measure.

Pitch, Half-steps, and Whole-steps on the Guitar

To play an accidental, we need to understand the terms ‘pitch’, ‘half-steps’ and ‘whole-steps’.
‘Pitch’ refers to the place each note has in its musical scale. When we play a note, the sound we hear is its pitch.

‘Half-steps’ and ‘whole-steps’ can also be called ‘semi-tones’ and ‘tones’ (in the UK, for example). They form the building blocks for all scales found in Western music.

  • Half step = 1 fret on guitar
  • Whole step = 2 frets on the guitar

Half-Step (semi-tone)

On a guitar, a half-step is the difference in pitch between any two neighboring frets. So if we move our finger from the second fret to the third fret, we’ve moved our finger a half-step.

Whole-step (tone)

A whole-step is the difference in pitch between three neighboring frets. So if we move our finger from the second fret to the fourth fret (skipping fret three), we’ve moved our finger a whole-step.

Guitar Fretboards – Which Way Is Up?

When we move our fingers on the fretboard, we change the pitch of a note either up or down.
Moving ‘up’ from fret 2 to 3 (ie. towards the body of the guitar) makes our note sound a half-step higher in pitch. This “sharpens” the note.

So up in pitch is down in space, and vice versa.

Moving ‘down’ from fret 3 to 2 (ie. towards the head of the guitar) makes our note sound a half-step lower in pitch. This flattens the note.

How Accidentals Sound in Music

Accidentals can add musical color and emotion to music.  Composers use them to move outside the basic notes of a key.

The main key of a piece of music feels like home.  We can expect and anticipate the notes and chords.

But when a composer moves one or more of the notes outside of the expected notes, it adds interest.  We may understand more of the emotion of the music.  Or we may understand more of the character the composer intends.

Musical ornaments may use accidentals.  And we may find accidentals used to pull us into a new set of home-base notes (i.e. modulating to a different key).

Likewise, improvised music, like jazz, often contains many accidentals.

Accidentals are a powerful musical tool to create mood and guide the music forward.


Allen Mathews

Hi, I’m Allen Mathews. 

I started as a folk guitarist, then fell in love with classical guitar in my 20’s. Despite a lot of practice and schooling, I still couldn’t get my music to flow well. I struggled with excess tension. My music sounded forced. And my hands and body were often sore. I got frustrated, and couldn’t see the way forward. Then, over the next decade, I studied with two other stellar teachers – one focused on the technical movements, and one on the musical (he was a concert pianist). In time, I came to discover a new set of formulas and movements. These brought new life and vitality to my practice. Now I help guitarists find more comfort and flow in their music, so they play more beautifully.
Click here for a sample formula.

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