Music Theory Cheat Sheet: Intervals, Chords, Scales & Keys

The 12 notes

Western music uses 12 pitches per octave, a semitone apart. Black-key notes have two names (enharmonic equivalents) — which one is used depends on the key.

C
C♯ / D♭
D
D♯ / E♭
E
F
F♯ / G♭
G
G♯ / A♭
A
A♯ / B♭
B

Intervals

Semitones	Symbol	Interval	Inversion
0	P1	Perfect Unison	P8
1	m2	Minor Second	M7
2	M2	Major Second	m7
3	m3	Minor Third	M6
4	M3	Major Third	m6
5	P4	Perfect Fourth	P5
6	TT	Tritone	TT
7	P5	Perfect Fifth	P4
8	m6	Minor Sixth	M3
9	M6	Major Sixth	m3
10	m7	Minor Seventh	M2
11	M7	Major Seventh	m2
12	P8	Perfect Octave	P1

Interactive intervals chart →

Common chord formulas (from C)

Symbol	Notes (from C)	Semitones
C	C, E, G	0–4–7
Cm	C, E♭, G	0–3–7
C+	C, E, G♯	0–4–8
C°	C, E♭, G♭	0–3–6
Csus2	C, D, G	0–2–7
Csus4	C, F, G	0–5–7
C5	C, G	0–7
C6	C, E, G, A	0–4–7–9
C6m	C, E♭, G, A	0–3–7–9
C7	C, E, G, B♭	0–4–7–10
CM7	C, E, G, B	0–4–7–11
Cm7	C, E♭, G, B♭	0–3–7–10
Co7	C, E♭, G♭, B♭♭	0–3–6–9
CM9	C, E, G, B, D	0–4–7–11–14
Cm9	C, E♭, G, B♭, D	0–3–7–10–14

All 89 chord formulas →

Scale formulas

Scale	Steps	Example from C
Major (Ionian)	W–W–H–W–W–W–H	C, D, E, F, G, A, B
Natural Minor (Aeolian)	W–H–W–W–H–W–W	C, D, E♭, F, G, A♭, B♭
Harmonic Minor	W–H–W–W–H–W+H–H	C, D, E♭, F, G, A♭, B
Melodic Minor	W–H–W–W–W–W–H	C, D, E♭, F, G, A, B
Dorian	W–H–W–W–W–H–W	C, D, E♭, F, G, A, B♭
Phrygian	H–W–W–W–H–W–W	C, D♭, E♭, F, G, A♭, B♭
Lydian	W–W–W–H–W–W–H	C, D, E, F♯, G, A, B
Mixolydian	W–W–H–W–W–H–W	C, D, E, F, G, A, B♭
Locrian	H–W–W–H–W–W–W	C, D♭, E♭, F, G♭, A♭, B♭
Major Pentatonic	W–W–W+H–W–W+H	C, D, E, G, A
Minor Pentatonic	W+H–W–W–W+H–W	C, D♯, F, G, A♯
Blues	W+H–W–H–H–W+H–W	C, D♯, F, F♯, G, A♯

All major & minor scales →

Key signatures

Signature	Major key	Minor key
—	C Major	A Minor
1♯	G Major	E Minor
2♯	D Major	B Minor
3♯	A Major	F♯ Minor
4♯	E Major	C♯ Minor
5♯	B Major	G♯ Minor
6♯	F♯ Major	D♯ Minor
7♯	C♯ Major	A♯ Minor
1♭	F Major	D Minor
2♭	B♭ Major	G Minor
3♭	E♭ Major	C Minor
4♭	A♭ Major	F Minor
5♭	D♭ Major	B♭ Minor
6♭	G♭ Major	E♭ Minor
7♭	C♭ Major	A♭ Minor

Order of sharps: F♯ C♯ G♯ D♯ A♯ E♯ B♯. Order of flats: B♭ E♭ A♭ D♭ G♭ C♭ F♭. The relative minor is always three semitones below its major key.

Diatonic chords in any key

Degree	I	ii	iii	IV	V	vi	vii°
Major keys	maj	min	min	maj	maj	min	dim

Degree	i	ii°	III	iv	v	VI	VII
Minor keys	min	dim	maj	min	min	maj	maj

Interactive circle of fifths →

Frequently asked questions

What should I learn first in music theory?

Start with the 12 notes and intervals, then the major scale and its key signatures, then triads and the diatonic chord pattern. Everything else — modes, seventh chords, progressions — builds on those four blocks.

How do I find the chords in a key?

Build a triad on each of the seven scale degrees using only the scale's notes. In every major key the qualities follow the same pattern: major, minor, minor, major, major, minor, diminished.

What is the fastest way to identify a key signature?

For sharps, the key is a half step above the last sharp; for flats, the key is named by the second-to-last flat. The relative minor sits three semitones below the major key.