The order of sharps and flats
Sharps appear in the order F C G D A E B. Each new sharp is added to the end of that sequence: G major has F♯, D major has F♯ and C♯, and A major adds G♯.
Flats use the reverse order: B E A D G C F. F major has B♭, B♭ major adds E♭, and E♭ major adds A♭. The position of each sign on the staff identifies the note it changes.
Find a major key from its signature
For sharp signatures, the major tonic is one semitone above the last sharp. With F♯ and C♯, the last sharp is C♯, so the major key is D.
For flat signatures with at least two flats, the second-to-last flat names the major key. B♭ and E♭ give B♭ major. Remember the one-flat exception, F major, and the signature with no sharps or flats, C major.
Major keys and their relative minors
Every major key shares its key signature with a relative minor. Find the relative minor tonic by moving down a minor third from the major tonic, or by taking the sixth degree of the major scale. C major and A minor share an empty signature; G major and E minor share F♯.
A key signature alone cannot tell you whether a complete piece is in the major or relative minor key. The music’s tonic and harmonic context matter. In Tonorino, the question explicitly asks for a major or minor key.
How to practice key signatures
- Start with Foundation: C, G, D, F, and B♭ major signatures.
- Count the signs, then check their order rather than guessing from the total alone.
- Switch Identify to Relative minor keys in Practice settings and connect each minor answer with its major partner.
- Choose Challenge when you are ready for signatures with up to four sharps or four flats.
Key signatures included in Tonorino practice
| Signature | Major key | Relative minor | Altered notes |
|---|---|---|---|
| None | C major | A minor | None |
| 1 sharp | G major | E minor | F♯ |
| 2 sharps | D major | B minor | F♯ C♯ |
| 3 sharps | A major | F♯ minor | F♯ C♯ G♯ |
| 4 sharps | E major | C♯ minor | F♯ C♯ G♯ D♯ |
| 1 flat | F major | D minor | B♭ |
| 2 flats | B♭ major | G minor | B♭ E♭ |
| 3 flats | E♭ major | C minor | B♭ E♭ A♭ |
| 4 flats | A♭ major | F minor | B♭ E♭ A♭ D♭ |
Common questions
Does a key signature identify only one key?
No. A major key and its relative minor share a signature. The exercise tells you which type of answer to choose.
How many key signatures are included?
There are nine signature patterns, from no sharps or flats through four sharps or four flats. Each can be practiced with a major or relative minor answer.
Are the extra notes in harmonic minor part of the key signature?
The raised seventh of harmonic minor is normally shown as an accidental in the music, rather than added to the key signature. A minor’s signature remains empty even when G♯ appears in a passage.
Make it a little daily habit.
Put the guide into practice with ten questions and feedback after every answer.
Start the key signature quiz