Diatonic Chords Chart: All 12 Keys and How to Read Roman Numerals
Diatonic chords are the seven chords you can build using only the notes of a key's scale. Most of the chords in a song come from these seven, so knowing the chart makes finding the key, transposing, playing by ear and songwriting much easier. This guide covers the diatonic chords of all 12 major keys, how to read the I–VII scale degrees (Roman numerals), common progressions and how minor keys work.
What are diatonic chords?
The C major scale is C D E F G A B (Do Re Mi Fa Sol La Ti). Take each note as a root and stack two more scale notes on top, skipping one each time, and you get seven chords: C (C-E-G), Dm (D-F-A), Em (E-G-B), F (F-A-C), G (G-B-D), Am (A-C-E) and Bm7♭5 (B-D-F plus A). These are the diatonic chords of the key of C.
In every key, the seven chord types come in the same order: the 1st, 4th and 5th are major, the 2nd, 3rd and 6th are minor, and the 7th is minor seven flat five (half-diminished). Writing this pattern as scale degrees (Roman numerals) lets you think in the same shape whatever the key.
| Degree | I | IIm | IIIm | IV | V | VIm | VIIm(♭5) |
|---|---|---|---|---|---|---|---|
| Type | Major | Minor | Minor | Major | Major | Minor | m7♭5 |
| Role | Tonic (stable) | Leads to V | Substitute for I | Subdominant | Dominant (wants to return to I) | Substitute for I; tonic of the relative minor | Substitute for V |
Diatonic chords in all 12 major keys
Here they are as triads (with VII written as m7♭5, as is customary). Sharps and flats follow each key's signature.
| Key | I | IIm | IIIm | IV | V | VIm | VIIm(♭5) |
|---|---|---|---|---|---|---|---|
| C | C | Dm | Em | F | G | Am | Bm7♭5 |
| D♭ | D♭ | E♭m | Fm | G♭ | A♭ | B♭m | Cm7♭5 |
| D | D | Em | F#m | G | A | Bm | C#m7♭5 |
| E♭ | E♭ | Fm | Gm | A♭ | B♭ | Cm | Dm7♭5 |
| E | E | F#m | G#m | A | B | C#m | D#m7♭5 |
| F | F | Gm | Am | B♭ | C | Dm | Em7♭5 |
| F# | F# | G#m | A#m | B | C# | D#m | E#m7♭5 |
| G | G | Am | Bm | C | D | Em | F#m7♭5 |
| A♭ | A♭ | B♭m | Cm | D♭ | E♭ | Fm | Gm7♭5 |
| A | A | Bm | C#m | D | E | F#m | G#m7♭5 |
| B♭ | B♭ | Cm | Dm | E♭ | F | Gm | Am7♭5 |
| B | B | C#m | D#m | E | F# | G#m | A#m7♭5 |
In F#, the VII chord is properly written E#m7♭5 (E# sounds the same as F, so you'll also see Fm7♭5). As seventh chords, the pattern becomes Imaj7, IIm7, IIIm7, IVmaj7, V7, VIm7 and VIIm7♭5 — in the key of C, Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7♭5.
Classic chord progressions in Roman numerals
If you remember progressions as scale degrees, you'll recognise the same progression even in a different key. Transposing becomes a matter of plugging the degrees into the chart above.
| Progression | Degrees | Key of C | Key of G |
|---|---|---|---|
| “Royal Road” progression (J-pop staple) | IV→V→IIIm→VIm | F G Em Am | C D Bm Em |
| Komuro progression | VIm→IV→V→I | Am F G C | Em C D G |
| Canon progression | I→V→VIm→IIIm→IV→I→IV→V | C G Am Em F C F G | G D Em Bm C G C D |
| Pop staple (“four-chord song”) | I→V→VIm→IV | C G Am F | G D Em C |
| Two-five-one | IIm→V→I | Dm G C | Am D G |
| Three-chord (I-IV-V) | I→IV→V | C F G | G C D |
Compare the columns and you'll see that in the key of G, Bm is about the only chord that needs a barre. That's why G and C are so common on guitar. To play songs in awkward keys with easier shapes using a capo, see how to avoid the F chord with a capo.
Transposing with scale degrees works like this. First turn the original chords into degrees (“F G Em Am” in C is IV, V, IIIm, VIm), then pick the chords with the same degrees from the target key's row (in D: G, A, F#m, Bm). It's less error-prone than counting semitones, and sharps and flats come out spelled correctly from the chart.
Diatonic chords in minor keys
A minor key uses the same seven chords as its relative major (the major key three semitones up). A minor shares its chords with C major, and E minor with G major, with the VIm chord treated as the tonic. For a song in A minor, that's Am (Im), Bm7♭5 (IIm7♭5), C (♭III), Dm (IVm), Em (Vm), F (♭VI) and G (♭VII).
| Minor key | Relative major | Seven chords (from Im) |
|---|---|---|
| Am | C | Am Bm7♭5 C Dm Em F G |
| Em | G | Em F#m7♭5 G Am Bm C D |
| Bm | D | Bm C#m7♭5 D Em F#m G A |
| Dm | F | Dm Em7♭5 F Gm Am B♭ C |
| Cm | E♭ | Cm Dm7♭5 E♭ Fm Gm A♭ B♭ |
Looking at which key's diatonic chords a progression fits lets you estimate the song's key. The step-by-step method is in how to find a song's key from its chords.
Looking up the chart quickly
The “Capo chart” tab of the Chord Transposer & Capo Calculator includes the diatonic chords of all 12 major keys. Tap a chord to see its diagram and hear it, so you can learn each key's sound by ear. Paste a chord sheet into the “Transpose” tab and the original key is detected automatically, and the chords are transposed as chords of that key.
FAQ
- What are the diatonic chords in the key of C?
- C, Dm, Em, F, G, Am and Bm7♭5. As seventh chords they are Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7♭5.
- What are the diatonic chords in the key of G?
- G, Am, Bm, C, D, Em and F#m7♭5. Many of them are easy to play on guitar, which makes G a popular key for singing and playing.
- How should I memorise diatonic chords?
- First learn the order of chord types — major, minor, minor, major, major, minor, m7♭5 — then apply it to the key's scale. Starting with the five keys C, G, D, A and E covers most guitar songs.
- What are Roman numerals like I, IV and V useful for?
- They describe a progression independently of the key, which makes transposing and playing by ear easier. “IV→V→IIIm→VIm” becomes F G Em Am in C and C D Bm Em in G instantly.
- How do minor-key diatonic chords differ from major?
- They use the same chords as the relative major, but the tonic is in a different place. A minor uses the same seven chords as C major, centred on Am. In minor keys, V is often changed to major (E or E7).
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