HearmonyThe Nashville Number System Explained, With a Worked Chart
The Nashville Number System writes chords as numbers instead of letter names. Each number is a degree of the major scale of the song's key, so in G major 1 is G, 4 is C, 5 is D and 6- is E minor. Because the numbers describe each chord's place in the key, the same chart works in any key: if the singer moves the song from G to D, nobody rewrites anything.
What is the Nashville Number System?
The Nashville Number System is a shorthand for chord charts used by session musicians, especially in country, gospel and pop studios in Nashville. It was developed in the late 1950s by Neal Matthews Jr., a member and vocal arranger of the Jordanaires, and adapted in the early 1960s by session musician Charlie McCoy for the rest of the band, according to the Nashville Number System entry.
It uses the same idea as Roman numeral analysis, written in ordinary digits. Where a theory class writes I–IV–V–vi, a Nashville chart writes 1 4 5 6-. Each number normally means one bar of the chord, and a full song fits on a single page.
The numbers in every key
To read a chart, you only need the major scale of the key and the chord quality on each degree. In a major key, 1, 4 and 5 are major; 2, 3 and 6 are minor (written with a minus sign); 7 is diminished and rarely used.
| Key | 1 | 2- | 3- | 4 | 5 | 6- | 7° |
|---|---|---|---|---|---|---|---|
| C | C | Dm | Em | F | G | Am | B° |
| G | G | Am | Bm | C | D | Em | F♯° |
| D | D | Em | F♯m | G | A | Bm | C♯° |
| A | A | Bm | C♯m | D | E | F♯m | G♯° |
| E | E | F♯m | G♯m | A | B | C♯m | D♯° |
| F | F | Gm | Am | B♭ | C | Dm | E° |
| B♭ | B♭ | Cm | Dm | E♭ | F | Gm | A° |
Chords from outside the key take a flat or sharp in front of the number. In G, ♭7 is F major and ♭3 is B♭ major; in C, ♭7 is B♭.
Nashville chart symbols
A few symbols cover most charts. Markings for rhythmic details vary a little between players and studios, so agree on them before the session; the ones below are the common core.
| Symbol | Meaning | Example in G |
|---|---|---|
| 1, 4, 5 | A major chord on that degree, one bar each | 1 = G, 4 = C |
| 6- or 6m | Minor chord | 6- = Em |
| 5⁷ | Dominant seventh chord | 5⁷ = D7 |
| 1maj7 or 1Δ | Major seventh chord | 1maj7 = Gmaj7 |
| 1/3 | Slash chord: the chord over a different bass note (a scale degree) | 1/3 = G/B |
| 4/5 | The 4 chord over the 5th in the bass | 4/5 = C/D |
| Underlined group | Split bar: two or more chords share one bar | 4 5 underlined = C and D, two beats each |
| Diamond around a number | Hit the chord once and let it ring | ◇1 = G held |
| Dot or accent over a number | Short, stabbed chord | A short hit on G |
| ♭7, ♭3 | Major chord on a lowered degree, borrowed from outside the key | ♭7 = F |
Watch the difference between 5⁷ and 7. A raised small 7 after a number adds a seventh to that chord; a 7 on its own is the chord on the seventh degree. Section labels (Intro, V for verse, Ch for chorus, Br for bridge) and repeat marks such as "x2" go at the left of each line.
A worked Nashville chart in G, transposed to D
Here is a short song form written as a number chart, with the chords it means in G and in D. Each number is one bar of 4/4. On paper, the split bar in the chorus would be underlined; here it is shown in brackets.
| Section | Number chart | In G | In D |
|---|---|---|---|
| Intro | 1 4 1 5 | G C G D | D G D A |
| Verse | 1 1 4 1 6- 4 5 5 | G G C G Em C D D | D D G D Bm G A A |
| Chorus | 4 1 5 6- 4 1 (4 5) ◇1 | C G D Em C G (C D) G held | G D A Bm G D (G A) D held |
The number column never changes. Move the song to D and every player reads the same chart in the new key, with nothing rewritten, which is the whole point. The method behind that mental shift is covered in the guide on how to transpose music.
How do you write minor keys in Nashville numbers?
There are two conventions for minor keys, and players disagree on which is better. Agree before the count-in.
- 1-based minor: the minor tonic is 1-. A song in A minor that goes Am–Dm–E7 is written 1- 4- 5⁷.
- Relative-major (6-based): the chart stays in the relative major key, so the minor tonic is 6-. The same song, charted in C, is 6- 2- 3⁷.
The 1-based version reads more naturally when the song stays minor. The 6-based version is easier when a song moves between a minor verse and a major chorus, because the numbers never change reference.
Why session players hear in numbers
Numbers match the way the ear hears chords: by function, not by letter. A 5 chord feels like tension that wants to go home to 1 in every key, and a 6- sounds like home turned wistful whether it is Em in G or Bm in D. A player who hears "that was the 4" can follow a song in any key, including one they have never played before.
The same thinking applies to single notes, where the numbers are scale degrees. Once you hear melodies as degrees and chords as numbers, a lot of popular music reduces to a handful of patterns; the overview of common chord progressions lists them as numerals you can copy straight into a chart.
How to write a Nashville chart by ear
Writing a number chart from a recording is ear training in its most practical form. Work in this order:
- Find 1. Hum the note the song wants to end on. Its chord is 1.
- Count the form. Count bars per section before naming any chord, and write a row of empty slots for each section.
- Follow the bass. The bass note usually gives the number. If it climbs a fourth from 1, you are probably on 4; a fifth, on 5.
- Check major or minor. A minor chord on 2, 3 or 6 gets a minus sign.
- Mark the details last. Splits, holds, pushes and slash chords go in once the numbers are right.
Start with songs you can already play. Write the chart in numbers from memory, then play it in a key you have never used for that song. If it sounds right, you have charted it correctly.
If telling 4 from 5 or 6- from 1 is the hard part, the ear training for beginners plan builds those skills one at a time.
Practice chord numbers in Hearmony
Hearmony's free Chord Numbers side quest teaches exactly this idea, using Roman numerals (I, IV, V and vi, which a Nashville chart writes as 1, 4, 5 and 6-). It starts with how chords get their numbers from the scale (in C major, C is I, F is IV, G is V), then the minor chords ii, iii and vi, then "Hear the numbers": a progression plays and you put numbers to it, or find the missing chord. The Progression Highway adventure takes the same skill further with I–IV–V, the pop progression, ii–V–I and cadences, always in random keys so the numbers, not the letters, carry the answer. Hearmony is available for iPhone.