Guide · Guitar theory
Roman numeral chords and Nashville numbers
A chord written by its place in the key: upper case for major (IV), lower case for minor (vi), ° for diminished. notation names each chord by its place in the key: upper case for major (I, IV, V), lower case for minor (ii, iii, vi) and a small circle for A chord with a minor 3rd and a flattened 5th, written °. It sounds tense, and is the vii° chord of a major key. (vii°). The Chord charts written with plain numbers for the degrees of the key (1 4 5 6m), so a song can be played in any key. does the same with plain numbers, writing a minor chord as 6m instead of vi.
Numbers for the chords of a key
Each chord takes the number of the scale note it is built on, from I for the first to vii for the seventh.
In C major: I = C, ii = Dm, iii = Em, IV = F, V = G, vi = Am and vii° = B°. The A chord written by its place in the key: upper case for major (IV), lower case for minor (vi), ° for diminished. says where the chord sits in the key, and its case says whether it is major or minor.
The same numerals in D major give D, Em, F♯m, G, A, Bm and C♯°. A progression written as I–IV–V describes both keys at once, which is the whole point.
What the extra symbols mean
A small circle means A chord with a minor 3rd and a flattened 5th, written °. It sounds tense, and is the vii° chord of a major key., a 7 adds a seventh, maj7 a major seventh, and ø a A diminished triad with a minor 7th added, written m7♭5 or ø7. It is the ii chord of a minor key. seventh.
With A triad with one more 3rd on top, the 7th, which makes four notes: G7, Cmaj7 and Am7 are seventh chords., C major reads Imaj7 = Cmaj7, ii7 = Dm7, iii7 = Em7, IVmaj7 = Fmaj7, V7 = G7, vi7 = Am7 and viiø7 = Bm7♭5. The V7 is the only A major chord with a minor 7th added, such as G7. It is the V7 of a key and pulls strongly to the I chord. in the key, the chord that pulls hardest back to I.
A flat or sharp in front of a A chord written by its place in the key: upper case for major (IV), lower case for minor (vi), ° for diminished. means the chord's The note a chord is named after and built up from. C is the root of C, Cm and C7. is outside the scale: ♭VII in C major is a B♭ chord, borrowed from C minor. A slash, as in V/V, means 'the V chord of the V chord', D in C major.
Numerals in a minor key
Minor keys are numbered from their own The home note of a key, and the chord built on it. Music in G major feels finished when it lands on G., so the home chord is a lower-case i.
In A minor: i = Am, ii° = B°, III = C, iv = Dm, v = Em, VI = F and VII = G. Notice the capitals: III, VI and VII are major chords in a minor key.
When a song uses the major V in a minor key, the A chord written by its place in the key: upper case for major (IV), lower case for minor (vi), ° for diminished. changes to match: V instead of v. Writing it that way shows at a glance that the seventh note of the scale was raised.
The Nashville number system
Nashville charts write the same idea with ordinary numbers, adding m for minor, and are read one number per bar.
In any major key the numbers are 1 2m 3m 4 5 6m 7°. A chart that says 1 5 6m 4 is I–V–vi–IV: C, G, Am and F in C, or D, A, Bm and G in D.
Session players use it because a singer can ask for a new key at the last minute and nobody needs a new chart. For minor-key songs, practice varies: some charts number from the minor key's own The home note of a key, and the chord built on it. Music in G major feels finished when it lands on G. (1m, 4m, 5), others from its The major and minor keys that share all seven notes and the same key signature, such as C major and A minor., so a song in A minor might be charted in C with 6m as home.
Why it is worth learning
Thinking in numbers makes Moving a song to a different key by shifting every chord by the same distance. instant, and it shows you why songs in different keys sound alike.
Once you hear that a song is 1 4 5, you can play it in any key, and the transposing guide shows how. You also start to notice that songs you love share the same few patterns, which makes learning new ones much faster.
Try it with a song you already play: write down its chords, find the key, then write each chord as a A chord written by its place in the key: upper case for major (IV), lower case for minor (vi), ° for diminished. underneath. After a few songs you will start hearing the numbers before you see them.
Every key page on GuitStart lists the chords with their numerals, and the chart of every key lines them up so you can read any numeral across all twenty-four keys.