How many sharps or flats does C major have?

Zero — C major is the only major key with an empty key signature.

What is the relative minor of C major?

A minor — same empty key signature, starting on the 6th degree of the C major scale.

What are the chords in the key of C major?

C major (I), D minor (ii), E minor (iii), F major (IV), G major (V), A minor (vi), and B diminished (vii°).

Key of C major — notes, key signature, and chords

C major is the centre of the western tonal system: zero sharps, zero flats, all white keys on the piano. Every other key signature is measured by its distance from C on the circle of fifths. It's the first scale most students learn and the default key for theory examples, ear-training drills, and beginner piano literature.

Key signature

0sharps or flats

C major is the only major key with no accidentals.

Diatonic chords

The seven triads built on each scale degree. These are the chords you hear used most in C major:

Roman	Chord	Quality	Notes
I	C	major	C · E · G
ii	Dm	minor	D · F · A
iii	Em	minor	E · G · B
IV	F	major	F · A · C
V	G	major	G · B · D
vi	Am	minor	A · C · E
vii°	B°	diminished	B · D · F

Common progressions

I–V–vi–IV in C is C–G–Am–F — the most-used progression in pop music. I–IV–V is C–F–G, the foundation of countless folk and rock songs. The ii–V–I jazz cadence is Dm–G–C. Because C major has no accidentals, it's the easiest key to compose, transpose, and demonstrate theory in.

Relative minor

The relative minor of C major is A minor — it shares the same key signature, just centred on the 6th degree of the C major scale (A). A piece can move between C major and A minor freely without any change of accidentals.

Common mistakes

The fact that C major uses only white keys can mislead beginners into thinking "white keys = C major." Other keys also use white keys (A minor uses the same set), and pieces in C major can borrow accidentals from other keys (chromatic passing tones, secondary dominants). The relative minor is A minor, which uses the same key signature.

Drill it

The Circle of Fifths trainer drills every key signature — C major included — with timed flash cards and best-time tracking.

Open the Circle of Fifths Trainer →Or try today's Etudle puzzle

Frequently asked

How many sharps or flats does C major have?: Zero — C major is the only major key with an empty key signature.
What are the notes in the C major scale?: C, D, E, F, G, A, B.
What is the relative minor of C major?: A minor — same empty key signature, starting on the 6th degree of the C major scale.
What are the chords in the key of C major?: C major (I), D minor (ii), E minor (iii), F major (IV), G major (V), A minor (vi), and B diminished (vii°).