What is a key signature?

A key signature is a set of sharps or flats placed at the beginning of a staff that tells you which notes are consistently raised or lowered throughout a piece. It defines the tonal center (key) of the music.

What is the order of sharps?

Sharps are added in this order: F#, C#, G#, D#, A#, E#, B#. A useful mnemonic is "Father Charles Goes Down And Ends Battle."

What is the order of flats?

Flats are added in this order: Bb, Eb, Ab, Db, Gb, Cb, Fb. The mnemonic "Battle Ends And Down Goes Charles Father" (the reverse of sharps) is commonly used.

How do I find the major key from sharps?

For sharp key signatures, the major key is one semitone above the last sharp. For example, if the last sharp is F#, the key is G major.

How do I find the major key from flats?

For flat key signatures, the major key is the second-to-last flat. For example, if the flats are Bb and Eb, the key is Bb major. C major (no flats) is a special case.

What is the relative minor?

Every major key has a relative minor that shares the same key signature. The relative minor starts on the 6th degree (3 semitones below) the major tonic. For example, A minor is the relative minor of C major.

What does 0 sharps/flats mean?

Zero accidentals means the key of C major (or A minor), which uses only the natural notes C D E F G A B — no sharps or flats.

Key Signature Finder

Name: Key Signature Finder
Availability: InStock
Author: Nham Vu

Select the number of sharps or flats to instantly identify the major key, its relative minor, and every note in the scale.

Select Key Signature

Accidental Type

Number of Accidentals

Accidentals in Key

None (C major / A minor)

Major Key

C Major

Relative Minor

A Minor

Notes in the Major Scale

Scale Degrees

Degree	Name	Note	Role in Minor

Circle of Fifths — Neighboring Keys

Fewer accidentals

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Current key

C major

More accidentals

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Summary

Select the number of sharps or flats to instantly identify the major key, its relative minor, and every note in the scale.

How it works

Choose whether your key signature uses sharps or flats.
Select the number of sharps or flats (0 through 7) using the slider or buttons.
The tool instantly displays the corresponding major key and its relative minor.
The specific sharp or flat notes added by the key signature are listed in order.
All seven notes of the major scale are shown with accidentals applied.
Use the circle of fifths reference to see adjacent keys for modulation.

Use cases

Quickly identify a key when reading sheet music.
Learn the order of sharps and flats and which keys they correspond to.
Find the relative minor for any major key signature.
Understand the circle of fifths by exploring adjacent key signatures.
Transpose music by comparing key signatures before and after.
Teach students how sharps and flats define major and minor keys.
Verify key signatures when composing or arranging music.
Identify key signatures encountered in sight-reading exercises.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu