How To Read Key Signatures | The Online Metronome

What is a Key Signature

A key signature is a collection of accidentals (sharp and flat symbols) that let you know what key a piece of music is in. These accidentals apply throughout the entirety of the piece unless otherwise noted either by a new key signature (called a key change) or with new accidentals attached to a note (one-off flat, sharp, or natural signs.)

A flat sign looks like this:

When you see it, you lower the pitch by a half step.

A sharp sign looks like this:

This symbol means you raise the pitch by a half step.

A natural sign looks like this:

It means that you play the pitch without modification.

A key signature will only contain one kind of accidentals, either sharps or flats, but never both. You will find it right next to the clef symbol at the beginning of the staff. Accidentals in the key signature always live on the staff line of the note they affect. Look below and you will see a sharp symbol on the F staff line and the C staff line. That means this key signature has two sharps: F-sharp and C-sharp.

Accidentals in the key signature are always written in the same order. Flats are written in this order: B, E, A, D, G, C, F Sharps are written in this order: F, C, G, D, A, E, B

All the Key Signatures

Below is a table that will let you know how many accidentals (sharps or flats) each key signature has. We show names in both the Major key and minor key. You will notice, when you write Major keys, you write the letter as a capital letter. Minor keys are always written in lower case.

Here is what key signatures with sharps look like across different clefs.

And here is what key signatures with flats look like across different clefs.

Enharmonic Equivalents

You might recall that sharp accidentals raise a note by a half step and flat accidentals lower the pitch by a half step. This means that some notes will sound the same but can be written in different ways. For example, B-flat could also be written as A-sharp. They will sound the same pitch. This can become complicated when notes are already a half step apart (E&F or B&C). Just imagine a piano keyboard. Keys that neighbor each other are a half step apart. The B key and the C key touch. The B-flat key (black) and the C key (white) have a note in between. This means they are a whole step apart. So, a B-sharp is not a C-flat, it is just a C.

If you would like to practice a piece of music in a given key, then we recommend checking out our piano keyboard tool. Just press the piano key that corresponds with your key signature.