Music Theoryafter A. Danhauser
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Key signatures: the chart and two rules to read any of them

A key signature is the group of sharps or flats written right after the clef. It applies to every note with that letter name for the whole piece, and it tells you the key. In this guide, you'll find the complete chart, then two simple rules that let you name any key signature, and finally a quiz to try them out.

Guide8 minUpdated October 2026
Key signatureAccidentalsMajorRelative minor
noneC majorA minor
1 sharp: F♯G majorE minor
2 sharps: F♯, C♯D majorB minor
3 sharps: F♯, C♯, G♯A majorF♯ minor
4 sharps: F♯, C♯, G♯, D♯E majorC♯ minor
5 sharps: F♯, C♯, G♯, D♯, A♯B majorG♯ minor
6 sharps: F♯, C♯, G♯, D♯, A♯, E♯F♯ majorD♯ minor
7 sharps: F♯, C♯, G♯, D♯, A♯, E♯, B♯C♯ majorA♯ minor
1 flat: B♭F majorD minor
2 flats: B♭, E♭B♭ majorG minor
3 flats: B♭, E♭, A♭E♭ majorC minor
4 flats: B♭, E♭, A♭, D♭A♭ majorF minor
5 flats: B♭, E♭, A♭, D♭, G♭D♭ majorB♭ minor
6 flats: B♭, E♭, A♭, D♭, G♭, C♭G♭ majorE♭ minor
7 flats: B♭, E♭, A♭, D♭, G♭, C♭, F♭C♭ majorA♭ minor

Rule 1: sharp keys

Find the last sharp, the one furthest to the right, and go up a half step: that's your major key. If the last sharp is C♯, you're in D major. If it's G♯, you're in A major. And sharps always appear in the same order: F, C, G, D, A, E, B.

Rule 2: flat keys

With flats, the second-to-last flat names the major key. With B♭, E♭ and A♭, for example, you're in E♭ major. Flats always appear in the order B, E, A, D, G, C, F. The only exception is F major, with a single flat, and that one you simply memorize.

Major or minor?

Don't worry if this part takes a little longer to click. Each key signature serves two keys: a major key and its relative minor, a minor third lower. The key signature alone can't tell you which one you're in, so look at the music. A minor piece usually raises its seventh degree with an accidental, like G♯ in A minor, and it ends on the minor tonic.

WorkshopKey Signature QuizFull screen
Your turn: name the key from its signature, in major and in minor.
Which MAJOR key has this key signature?

Method: with sharps, the major tonic is a half step above the last sharp; with flats, it is the second-to-last flat (F major for one flat). The relative minor is a minor third lower.

WorkshopPrintable worksheetsFull screen
Here is a printable key signature worksheet, with its answer key.

Each sheet has a number: write it down to get exactly the same sheet again (handy to give a whole class the same homework).

Key signatures · trebleFor each key signature, write the major key and its relative minor.
Name : __________________Date : __________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

Major : ____________

Minor : ____________

themusictheorycourse.comSheet no. 1197
Key signatures · treble · answer key

Major : E major

Minor : C♯ minor

Major : B♭ major

Minor : G minor

Major : A♭ major

Minor : F minor

Major : A major

Minor : F♯ minor

Major : F major

Minor : D minor

Major : G major

Minor : E minor

Major : D major

Minor : B minor

Major : E♭ major

Minor : C minor

themusictheorycourse.comSheet no. 1197

Frequently asked questions

How do you identify a key signature?

With sharps, go up a half step from the last sharp. With flats, take the second-to-last flat. A single flat means F major, and no sharps or flats at all means C major, or A minor.

What is the order of sharps and flats?

Sharps come in the order F, C, G, D, A, E, B. Flats come in the same order reversed: B, E, A, D, G, C, F.

How many key signatures are there?

There are fifteen: one with no sharps or flats, seven with one to seven sharps, and seven with one to seven flats. Each one serves a major key and its relative minor, which makes thirty keys in total. Some of them sound the same, like B major and C♭ major.

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