Key Signature Calculator

This key signature calculator consists of two parts: a music key finder, which determines what key you're in based on the number of sharps/flats; and the key signature finder, which finds the flats or sharps you need in a particular key.

In the text below, we'll cover some theories on the subject, including:

• What is a key signature in music? (key signature definition);

• How to identify key signatures;

• How to use the music key finder app; and

• A list of key signatures.

A key in music tells us which set of notes we use in a song. We say a piece is in the key of C major when we use only (or almost only) notes in the C major scale. Learn more about music scales by visiting our music scale calculator.

A key signature is a section of sheet music that tells us what key we're in and what notes on the sheet have sharps or flats. The section is located at the beginning of each line, between the clef and time signature:

There are 15 key signatures - 7 with flats, 7 with sharps, and one with no sharps or flats. Take a look at the lists of key signatures:

Each key signature corresponds to one major key and its relative minor. A relative minor key is the key which uses the same set of notes as a major key but has a different tonic. For example, C major consists of the same sounds as A minor:

C major: C, D, E, F, G, A, B,

A minor: A, B, C, D, E, F, G.

As you can see, both keys use no sharps or flats, so if you can't see any symbols next to a clef, it means you're either in C major or A minor.

There are certain tricks you can use to identify key signatures. To find what key you're in, you can:

• Find the note with the last sharp and go a tone up.

  For example, if you have one sharp on the fifth line of the staff, it means you'll have to raise F. If we go a tone up from F we get a G. The key with one sharp is G major.

• If you're dealing with flats, read the penultimate flat — this will be the key.

  For example, you have 3 flats, and the penultimate is B♭ — which means you're in B♭ major.

• To find the relative minor key, count down 3 notes from the root of the major key.

  For example, the D major scale consists of D, E, F#, G, A, B, C#, D. Let's find the third note from the end: D, C#, B. B minor is the relative minor of D major.

To find whether you're in a minor or major key, you can check the first and last bass note or chord. The note will determine the key in the majority of music.

What if you want to know how many sharps or flats a particular key has (for example, when you write sheet music yourself)? A useful key signature chart called the circle of fifths can help you in such situations:

The major keys are placed in the outer circle and their relative minors are in the inner circle. Between them, you'll see the corresponding flats and sharps. The adjacent notes are a perfect fifth apart (hence the chart's name). Going from C, we add sharps going clockwise and flats going counterclockwise.

To remember the order of sharps and flats, you can use this popular mnemonic:

• Father Charles Goes Down And Ends Battle (for sharps)

  F, C, G, D, A, E, B

• Battle Ends And Down Goes Charles Father (for flats)

  B, E, A, D, G, C, F

To recreate the key signature chart from memory:

1. Recall the sentence: "Father Charles Goes Down And Ends Battle".

2. Draw a circle with 12 evenly spaced places for notes.

3. Remember C has no sharps or flats; write it at the top of the circle.

4. Starting from the place to the left from C and going clockwise, enter the first letters of the mnemonic: F, (C), G, D, A, E, B.

5. After "B," continue filling the circle with first letters from a shortened part of the mnemonic: "Goes Down And Ends Battle". Add a flat to each letter. You'll have (G♭, D♭, A♭, E♭, B♭)

6. You can write down the number and names of sharps on the right part of the circle and flats on the left using the same mnemonic.

Now that we know how to remember key signatures, let's go through some exercises.

Let's go through some examples to better learn how to find key signatures.

Example 1: find the 3 sharps key.

• To recall the first three sharps, we use the mnemonic "Father Charles Goes (...)" (we don't need to recall the rest of the sentence) and get the first letters: F, C, G.
• We take the last note - G - and go a tone up.
• We get A - The 3 sharps key is an A major key signature.

Example 2: find the 6 flats key.

• We recall the order of flats: "Battle Ends And Down Goes Charles' Father".
• We enumerate the first letters of the first 6 words: B, E, A, D, G, C.
• We read the penultimate note - G - and add a flat, which gives us G♭. The 6 flats key is G♭ major.

Example 3: find what D major's key signature is.

• We again use the mnemonic and enumerate the keys until we get to D. We recall C has no sharps or flats:

  (Father)

  Charles - C - 0 sharps

  Goes - G - 1 sharp

  Down - D - 2 sharps

• We now know D major has 2 sharps.

• To get the names of the first 2 sharps, we need the first two words of the mnemonic: "Father Charles (...)" - F and C. This means D major has 2 sharps - F# and C#, so the whole scale would be: D, E, F#, G, A, B, C#.

Example 4: identify B minor's key signature

• We can list the order of major keys in the circle of fifths and check which one is relative to B minor. To find the relative minor, we list 3 notes down the major scale. There we go:

  Charles - C

  3 notes down the scale are C, B, and A. Therefore, the relative minor of C major is A minor.

  Goes - G

  3 notes: G, F#, E. Relative minor: E.

  Down - D

  3 notes: D, C#, B. Relative minor: B.

  We've found it. B minor is a relative key of D major. Its key signature is the same: 2 sharps - F# and C# (see the previous example).

It takes a while to check key signatures this way so let's see how the key signature calculator can help you when you need to get the answer on the go.

This key signature calculator has two functionalities:

• A key finder (you know the number of sharps/flats and want to check the key);

• A key signature finder (you want to check what sharps/flats a key has).

Choose one of the above options in the first field of the key signature calculator.

If you chose the first option, enter the number (from 0 to 7) and type of symbols in the key signature. The key finder will tell you what major and minor key corresponds to the given signature.

If you chose the second option from the key signature calculator, choose the key's quality (major/minor) first. It will change the list of notes below, from which you need to select the root note. Once you do, the key signature finder will tell you how many and which flats or sharps the specified key has.

Note: we didn't include theoretical keys (key signatures with double flats and sharps) in the key finder as they're rarely used.

The keys G major and E minor have 1 sharp - F#. You can find it by moving along the circle of fifths. G major adjoins C, which has no sharps or flats.

The keys with 2 sharps are: D major and B minor. The two sharps are F♯ and C♯. If you move along the circle of fifths, you'll see that D major is 2 steps clockwise from C. The number of steps clockwise corresponds to the number of sharps and steps counter-clockwise is the number of flats.

A major key has 3 sharps: F♯, C♯, G♯. A major's relative minor is F♯ minor, therefore it has the same key signature. You can remember it by using a mnemonic Father Charles Goes Down And Ends Battle. The first letters denote keys and after C you count the number of sharps: G - 1, D - 2, A - 3.

Keys E major and C♯ minor have 4 sharps: F♯, C♯, G♯, D♯. You can use the circle of fifths to check it.

B major and G♯ minor keys have 5 sharps: F♯, C♯, G♯, D♯, A♯. You can use the mnemonic Father Charles Goes Down And Ends Battle to remember it. The first letters of words mark the order of keys. They are ordered according to the number of flats and sharps.

The keys with 6 sharps are F♯ major and D♯ minor. The 6 sharps are: F♯, C♯, G♯, D♯, A♯, and E♯. F♯ major is enharmonically equivalent to (use same pitches as) G♭ major. D♯ minor's equivalent is E♭. Both have 6 flats.

C♯ major and A♯ minor have 7 sharps: F♯, C♯, G♯, D♯, A♯, E♯, and B♯. These keys can be written as D♭ major and B♭ minor, respectively.

Keys F major and D minor have 1 flat - B♭. Memorise the circle of fifths to remember keys' number of flats.

Keys B♭ major and G minor have 2 flats: B♭ and E♭. You can find it by counting the steps from C counter-clockwise along the circle of fifths.

The 3-flats keys are E♭ major and C minor. The three flats are B♭, E♭, and A♭. To remember the number of flats in a key, use the following mnemonic: Battle Ends And Down Goes Charles' Father. Count from 2: B - 2, E - 3, A - 4, D - 4...

A♭ major key and F minor key have 4 flats: B♭, E♭, A♭, and D♭. To find this out, you can enumerate notes starting from C and going a fifth down: C, F, B♭, E♭, A♭. C has no flats, F has 1, B♭ has 2, E♭ has 3, A♭ has 4.

D♭ major and B♭ minor are the keys with 5 flats: B♭, E♭, A♭, D♭, and G♭. You can use the circle of fifths to find the number of flats particular keys have.

The 6-flats keys are G♭ major and E♭ minor. Their flats are: B♭, E♭, A♭, D♭, G♭, and C♭. You'll find these keys at the bottom of the circle of fifths.

C♭ major and its relative minor key - A♭ minor - have 7 flats: B♭, E♭, A♭, D♭, G♭, C♭, and F♭. These keys are the most difficult ones to play on piano. It's probably better to use B major and G♯ minor, which use the same pitches but have only 5 sharps.

C major and A minor keys have no sharps or flats. These are the easiest keys to play on piano.

The key of G major has 1 sharp: F♯. You can count the number of sharps by going clockwise along the circle of fifths. The number of steps away from C is the number of sharps.

C major key has no flats no sharps. Maybe that's why it's so popular.

The order of flats in a key signature is as follows: B♭, E♭, A♭, D♭, G♭, C♭, F♭. It may be easier to remember if you use a popular mnemonic:

Battle Ends And Down Goes Charles Father