How to Read Sheet Music: Key Signatures and Accidentals

This is an authorized transmission from the ghost of Herr Wolfgang Amadeus Mozart to his beloved apprentice, you.

You've learned the names of notes and how to read rhythm. You're making progress, apprentice! But I've been holding back on you, lest your head explode prematurely. There's something I mentioned earlier but didn't fully explain: those groups of sharps (#) and flats (♭) you sometimes see having a party after the clefs.

Those are key signatures, and they serve to make music more readable. Below is the same music, represented in two different ways (hit play and check):

As you learned in how to read sheet music, sharps (#) and flats (♭) unlock the black keys on the piano. A sharp raises a note in pitch by a half step, e.g. C -> C#, and a flat lowers it by a half step, e.g. D -> D♭. (Reminder: on the piano a half step takes you to the next or previous key.)

There are 12 notes in every octave. Verify this for yourself by counting all white and black keys from middle C to the next C. A key is a group of 7 out of those 12, chosen using one of a few top-secret patterns, known only to the gods. Think of it as a color palette for a piece of music.

For example C major consists of the 7 white keys in every octave: C, D, E, F, G, A, B (no sharps or flats).

E♭ major below, consists of the notes E♭, F, G, A♭, B♭, C, D. Next to the clef there are three flats: E♭, A♭, B♭ - the key signature. This tells us that every E's, A's and B's in the piece should be flatted, unless otherwise specified. Just think of how many ♭ symbols are saved this way. This invention alone bumped the average age composers get carpal tunnel from 28 to age 32.

Key signatures are convenient, but sometimes you might want to play notes outside the key, you crazy rebel. When you do, just add a # or a ♭ symbol for that note as before. These departures from the key signature are called accidentals. I was working on getting them renamed to oopsies for clarity when I died.

Hm, what if the key signature says E♭ but you need to play an E? Good question, apprentice. There is a third accidental I've been hiding from you: the natural (♮). It cancels out any sharp or flat from the key signature or from a previous accidental. Here's what you would see if you needed to play an E while in the key of E♭ major:

Last thing: while key signatures affect all octaves, accidentals only affect the line or space they're drawn in and only for the rest of the measure.

C Major

The default key signature, no sharps or flats.

B♭ Major

B♭ major has two flats: B♭ and E♭.

F# Major

F# major has 7 sharps! Imagine having to write all those out without a key signature...

See below a few examples. For each one, write out 1) all the flats/sharps in the key signature and 2) all the notes. Then highlight the answer line to check your answers.

Answer (highlight below to reveal):

Answer (highlight below to reveal):

• A key is a group of 7 magical notes chosen by the gods from the 12 notes of the octave
• The key signature tells you which notes are flat or sharp in a key, and applies across ALL octaves, until the next key signature or the end of the piece
• Accidentals are an escape hatch from the key. They come in three flavors (#, ♭, ♮), only affect the line or space they're drawn in, and only for the rest of the measure

Next: Now that you understand notes, rhythm, key signatures and accidentals, you're ready to tackle more complex pieces. And stay tuned for more lessons from beyond the grave. Amadeus out.