Sharps and Flats on Guitar: The One-Fret Rule Explained

You open a chord chart and see F#m, or a song in Bb, and your brain stalls. Where is F sharp? Is B flat the same as A sharp? Sharps and flats on guitar look like extra theory homework, but they are the easiest notes on the neck to find once you know one simple rule.

In this short GuitarZoom lesson, the instructor shows the whole idea in under 20 seconds. Learn where the plain notes are first: F on the 1st fret, G on the 3rd and A on the 5th of the low E string. Then every sharp is one fret up from its note. Below we turn that into a full beginner lesson, with tab, a note chart, the A# vs Bb question and a short practice plan.

Video: How Sharps and Flats Finally Make Sense, GuitarZoom. Watch on YouTube

What sharps and flats mean on guitar

Music uses only seven letter names: A, B, C, D, E, F and G. These are the natural notes. After G, the letters start again at A.

But there are 12 different notes before the pattern repeats, not 7. The other 5 notes sit in the gaps between the letters. We name them with two symbols:

• Sharp (#) means "one step higher". F# (F sharp) is one note above F.
• Flat (b) means "one step lower". Bb (B flat) is one note below B.

On guitar, that one step is the smallest move you can make: one fret. Move one fret toward the body and the note goes up. Move one fret toward the headstock and it goes down. That is all sharps and flats on guitar really are.

Step 1: Know where the natural notes are

This is the key point in the video. You can't find F# if you don't know where F is. So start with the plain letters on the low E string (the thickest string).

Notice two things. First, at fret 12 you are back to E, one octave higher. Second, some notes are two frets apart (F to G, G to A) and some are only one fret apart (E to F, B to C). That is the most important pattern on the whole fretboard.

Natural notes on the low E string

E|--0--1--3--5--7--8--10--12--|
    E  F  G  A  B  C  D   E

Say the note name out loud as you play each fret. Do it slowly until you can find F, G and A without counting.

Step 2: Use the one-fret rule

Once you truly know where a natural note is, the sharp is easy. The instructor puts it simply: if you know where G is and someone asks for G#, you just move up one fret. Same with F and F#.

Natural note, then its sharp (low E string)

E|--1--2--|   F, then F#
E|--3--4--|   G, then G#
E|--5--6--|   A, then A#

Flats work the same way in the other direction. Find the natural note, then move down one fret.

Natural note, then its flat (low E string)

E|--7--6--|   B, then Bb
E|--5--4--|   A, then Ab
E|--3--2--|   G, then Gb

Look at the tab closely. A# is fret 6, and Bb is also fret 6. G# is fret 4, and Ab is also fret 4. This leads to the question almost every beginner asks.

Is A# the same as Bb?

Yes. On guitar, A# and Bb are the exact same note. They are on the same fret and sound the same. A# means "one fret above A". Bb means "one fret below B". Since A and B are two frets apart, both names point to the fret in the middle.

Notes that sound the same but have different names are called enharmonic notes. Here are all five pairs:

So why have two names? It depends on the key or chord you are in. Music likes to use each letter once per scale, so some keys are written with sharps and others with flats. A song in the key of F, for example, uses Bb, not A#. As a beginner, you don't need to worry about which name is "right". Just know they are the same fret. If you want to put this to work, our B flat chord lesson shows easy and barre shapes for Bb.

Why there is no sharp between E and F, or B and C

Look back at the note chart. E is on the open string and F is on fret 1. There is no fret in between, so there is no note in between. The same is true for B (fret 7) and C (fret 8).

An easy way to remember it: "B-C, E-F, no sharp in between." Every other pair of letters has one sharp/flat note between them. This is why the 7 letters plus 5 sharps/flats add up to 12 notes.

Here is the full 12-note sequence, starting from A:

A  A#/Bb  B  C  C#/Db  D  D#/Eb  E  F  F#/Gb  G  G#/Ab  (A again)

Each step in that line is one fret on any string.

Step 3: Do the same on the A string

The one-fret rule works on every string. The A string (the 5th string) is the next one to learn, because many chord shapes start their root note there.

Natural notes on the A string

A|--0--2--3--5--7--8--10--12--|
    A  B  C  D  E  F  G   A

Now try finding sharps and flats from these landmarks. C is fret 3, so C# is fret 4. D is fret 5, so Db is fret 4 too. Same fret, two names again. Once you can do this on the two lowest strings, you can name the root of most chords you will play as a beginner. For a deeper method to learn every string, see how to memorize the fretboard notes for life.

A simple practice plan

Ten minutes a day is enough. The goal is to know the natural notes so well that the sharps and flats are automatic.

Next, test yourself with real chord names. When you see F#m or Bb in a song, find the root note on the low E or A string before you play the chord. If you are just starting with chords, our guitar chords for beginners guide is a good place to use this skill.

Want to go further with keys, scales and how chords are built? Music Theory Made Easy walks you through guitar theory step by step.

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