The Nashville number system replaces the letter names of chords with numbers. Each number
is a degree of the major scale of the key the song is in, so the same chart can be played in any key
without rewriting it. It is a shorthand for transposition, not a separate theory.
How the numbers work
A number stands for the chord built on that degree of the major scale. In C, 1 is C, 4 is F, 5 is G,
6m is Am.
The chord quality follows from the major scale and does not need to be written: the chords on 2, 3
and 6 are minor, the chord on 7 is diminished, the rest are major.
A dash or m after the number means minor; a 7 means a dominant seventh; a small arrow or a triangle
means major seventh. Chords outside the key are written with their alteration, for example b7 for a
major chord on the flat seventh degree.
To change key, change the letter the numbers are counted from. The numbers stay as they are. This is
their entire purpose: a band can agree on a key and read the same chart.
The seven degrees
Number
Numeral
Triad quality
Seventh chord
What the seventh chord is
1
I
major
major seventh
A major triad with a major seventh added. The interval between the third and the seventh is a major third, which is why the chord sounds stable.
2
ii
minor
minor seventh
A minor triad with a minor seventh added. The interval between the third and the seventh is a perfect fifth.
3
iii
minor
minor seventh
A minor triad with a minor seventh added. The interval between the third and the seventh is a perfect fifth.
4
IV
major
major seventh
A major triad with a major seventh added. The interval between the third and the seventh is a major third, which is why the chord sounds stable.
5
V
major
dominant seventh
A major triad with a minor seventh added. The interval between the third and the seventh is a diminished fifth, which is unstable and wants to resolve inwards.
6
vi
minor
minor seventh
A minor triad with a minor seventh added. The interval between the third and the seventh is a perfect fifth.
7
vii°
diminished
half-diminished seventh
A diminished triad with a minor seventh added. Three minor thirds separated by a major third.
The chords for the twelve keys
Each row is a key, each column a number: 1, 2, 3, 4, 5, 6, 7. Minor and diminished chords are marked.
In a minor key the numbers run from the minor tonic. The qualities below are those of the natural
minor scale, which is why the third chord comes out major and the fifth minor; in practice the fifth
chord is usually played as a major or dominant, borrowed from the harmonic minor scale.
Key
1
2
3
4
5
6
7
C minor
Cm
Ddim
D#
Fm
Gm
G#
A#
C# minor
C#m
D#dim
E
F#m
G#m
A
B
D minor
Dm
Edim
F
Gm
Am
A#
C
Eb minor
Ebm
Fdim
Gb
Abm
Bbm
B
Db
E minor
Em
F#dim
G
Am
Bm
C
D
F minor
Fm
Gdim
Ab
Bbm
Cm
Db
Eb
F# minor
F#m
G#dim
A
Bm
C#m
D
E
G minor
Gm
Adim
A#
Cm
Dm
D#
F
Ab minor
Abm
Bbdim
B
Dbm
Ebm
E
Gb
A minor
Am
Bdim
C
Dm
Em
F
G
Bb minor
Bbm
Cdim
Db
Ebm
Fm
Gb
Ab
B minor
Bm
C#dim
D
Em
F#m
G
A
Common progressions
Numerals
Numbers
Where it turns up
I–IV–V
1 4 5
the three-chord foundation of most Western popular music
I–V–vi–IV
1 5 6m 4
the four-chord loop of contemporary pop
vi–IV–I–V
6m 4 1 5
the same loop starting on the relative minor
ii–V–I
2m 5 1
the cadence that defines jazz harmony
I–vi–ii–V
1 6m 2m 5
the circle-of-fifths turnaround
twelve-bar blues
1 1 1 1 4 4 1 1 5 4 1 5
the standard blues form, with the fifth chord in the second half
I–bVII–IV
1 b7 4
a modal rock progression that borrows the flat seventh from the minor key
Every chord above has its own page under Chords.
The keys are described under Key signatures, and the
transposition of these numbers by a capo is on the capo chart.
Related
ReferenceIntervals12 intervals, with compound extensions
ReferenceCircle of fifths12 keys, relative minors, order of accidentals