The Nashville Number System
Write a progression once, play it in any key. The Nashville Number System charts chords as scale-degree numbers — 1–4–5 instead of G–C–D — so a single chart re-keys itself the instant the singer needs it higher or lower. The player below is the system in action: the pills are the numbers, and the key selector is the re-key.
What the numbers mean
Every major key has seven chords, one on each note of the scale. The Nashville system simply numbers them 1 through 7. The quality is fixed by the scale: 1, 4 and 5 are major; 2, 3 and 6 are minor; 7 is diminished. So “1–4–5” always means the three major chords — the country backbone — whatever key you are in.
This is the same idea as the Roman numerals theory uses (1 = I, 4 = IV, 5 = V); the players on this page show the Roman form, so read the pills as numbers.
Why it re-keys instantly
Because the numbers describe function, not letters, the chart never changes when the key does. Take the four-chord pattern 1–5–6–4 and move it through keys with the selector — the numbers stay put while the chords underneath rename themselves:
The numbers in three keys
The same seven numbers, spelled out in the three keys country uses most. Read across a row to see how one number becomes three different chords:
| # | Quality | Key of G | Key of C | Key of D |
|---|---|---|---|---|
| 1 | Major | G | C | D |
| 2 | minor | Am | Dm | Em |
| 3 | minor | Bm | Em | F♯m |
| 4 | Major | C | F | G |
| 5 | Major | D | G | A |
| 6 | minor | Em | Am | Bm |
| 7 | diminished | F♯° | B° | C♯° |
Hear each number
The seven chords of the key of G, by number. Tap through them to connect each number to its sound and its shape on the keys:
G – B – D
Frequently asked questions
What is the Nashville Number System?
It is a way of writing chord progressions using the numbers 1 through 7 — the scale degrees of the key — instead of letter chords. A progression charted as 1–4–5 means "the I, IV and V chords of whatever key we are in." Nashville session players invented it so charts could be written once and played in any key.
How do the numbers map to chords?
In any major key, number 1 is the major chord built on the tonic, and the rest follow the scale: 1, 4 and 5 are major; 2, 3 and 6 are minor; 7 is diminished. So in G, 1–4–5 is G–C–D; in C it is C–F–G; in D it is D–G–A. Same numbers, different letters.
Why do country and session musicians use numbers instead of chords?
Because singers need songs in different keys, and bands re-key on the spot. A number chart does not change when the key changes — 1–4–5 is 1–4–5 in every key — so one chart works for everyone. It also makes the harmonic function obvious at a glance, which speeds up learning and arranging.
Is the Nashville Number System the same as Roman numerals?
They describe the same thing — chords by scale degree — but with different notation. Music theory uses Roman numerals (I, ii, V) where upper- and lower-case show major and minor. Nashville charts use plain arabic numbers (1, 2, 5) with other marks for quality. The players above show Roman numerals; read 1 = I, 4 = IV, 5 = V.