πΆ Diatonic Chord Finder
Every chord that naturally belongs in any key, with numerals and notes.
Diatonic chords
How to Use This Chord Finder
Pick any of the twelve keys and choose major or natural minor. The tool instantly lists all seven diatonic triads with their roman numerals, chord names, and the three notes in each chord, plus the relative major or minor key for quick reference.
Select the Key you are working in. If you know the key signature (for example two flats), that is Bb major or G minor; the relative key line under the results confirms the pairing.
Choose Major or Minor. Minor here means natural minor, the default minor scale; if your song uses a major V chord, that is the common harmonic-minor borrowing and it still belongs to the family.
Read the seven chords with their numerals. The Function column tells you each chord\'s role: tonic (home), subdominant (movement away), or dominant (tension pulling home).
Use the note spellings to build voicings on piano or to check that a chord from another source really belongs. The relative key reminder helps when a song drifts between major and its relative minor.
How Diatonic Chords Are Built
Take the C major scale (C D E F G A B) and build a triad on each note by stacking two thirds. On C you get C E G, a major triad: the I chord. On D you get D F A, minor: the ii chord. Continue up the scale and the pattern of qualities is locked in by the math of the scale itself: major, minor, minor, major, major, minor, diminished. Transpose the whole machine to any root and the qualities repeat exactly, which is why G major gives G Am Bm C D Em F#dim.
Natural minor works the same way on its own scale. A minor (A B C D E F G) yields Am, Bdim, C, Dm, Em, F, G. The v chord is minor here, and that weak dominant is precisely why composers historically raised the seventh scale degree to create harmonic minor: Em becomes E major, and the V-i cadence regains its powerful pull. When you see a major V in a minor key, you are hearing that centuries-old fix in action.
Worked Example
Find the chords in Eb major. The Eb major scale is Eb F G Ab Bb C D. Stacking thirds: I = Eb (Eb G Bb), ii = Fm (F Ab C), iii = Gm (G Bb D), IV = Ab (Ab C Eb), V = Bb (Bb D F), vi = Cm (C Eb G), viiΒ° = Ddim (D F Ab). A songwriter in Eb now knows that Ab, Bb, and Cm are all safe choices, and that Ddim exists for tense turnaround moments.
Now the relative minor, C minor. Its scale is C D Eb F G Ab Bb, giving i = Cm, iiΒ° = Ddim, III = Eb, iv = Fm, v = Gm, VI = Ab, VII = Bb. Compare with Eb major above: the same seven chords, just starting from a different home. That shared pool is why songs constantly blur the line between a major key and its relative minor, and why the finder shows the relative key for every selection.
Practical Tips
Memorize the Nashville-style numbers for one key and you have them all. If you know that in G major the chords are G(1) Am(2) Bm(3) C(4) D(5) Em(6) F#dim(7), then in D major the 4 chord is G and the 5 is A without any new memorization. Session players think entirely in these numbers so a singer can call "take it down to E" and the band transposes instantly.
When writing, start progressions on the tonic and end phrases on either the tonic (resolved) or the dominant (unresolved, wants to continue). The ii and IV chords are the smoothest bridges between tonic and dominant, which is why ii-V-I and IV-V-I turnarounds appear in every genre. And if a chord you love is not in the diatonic list, keep it anyway: the list describes the home neighborhood, not a fence.
Frequently Asked Questions
What are diatonic chords?
Diatonic chords are the seven triads built from the notes of a key's scale, one on each scale degree. In C major they are C, Dm, Em, F, G, Am, and Bdim. Because they share the key's notes, they sound naturally at home together, which is why most songs use only diatonic chords.
Why are some chords major and some minor in a key?
The chord quality comes from stacking thirds on each scale degree using only the key's notes. In major keys, degrees 1, 4, and 5 stack into major triads, degrees 2, 3, and 6 into minor triads, and degree 7 into a diminished triad. This pattern is identical in every major key; only the root notes change.
What is the difference between the major and minor diatonic sets?
Major keys give I ii iii IV V vi vii\u00B0, while natural minor keys give i ii\u00B0 III iv v VI VII. Notice the minor set has a minor v chord, which is why minor-key songs often borrow the major V from harmonic minor: it creates a stronger pull back to the tonic i.
Which diatonic chords are most important?
The I (tonic), IV (subdominant), and V (dominant) are the primary chords that define the key. The ii, iii, and vi are secondary chords that add color, and vii\u00B0 is the least used because its tense, unstable sound usually resolves straight to I. Learn the primaries first; they carry most songs.
Can I use chords outside the diatonic set?
Absolutely, borrowed and chromatic chords are everywhere in real music. Common visitors include the borrowed iv in major keys, secondary dominants like V/V, and the Neapolitan chord. Think of the diatonic set as home base: you can travel, but listeners feel where home is.
How do I find the key of a song from its chords?
List the chords and find which key's diatonic set contains all (or most) of them. The chord that feels like home, usually where phrases resolve, is likely the tonic. Our finder lets you test candidate keys instantly: pick a key and check whether the song's chords appear in its seven.