Diatonic chords are the seven chords available in a given key. The chords that show up in a song usually fall within these seven.
Before the explanation, listen for yourself. Try pressing the tool’s seven “chords available in this key” buttons below, from left to right.
If you can’t hear anything, turn off silent mode and reload the page.
- Pick a key
The top row is sharp keys, the bottom row is flat keys. Picking one rewrites the seven chords for that key. - Press the seven buttons
Each press adds a bar, and the fingering appears on the keyboard. The small numbers (Ⅰ・ⅱ・ⅲ…) are scale degrees. - Play it back
It plays in the order you arranged them. You can change the tempo too.
Play through the seven in order and you’ll hear that every one connects smoothly. That’s because they’re all built from the same seven notes.
“What chord should come next?” — everyone hits this wall when they start learning chords. Instead of choosing from 108 chords, you’re choosing from seven. Once you can think that way, both accompaniment and composition become far more manageable.
This article walks through how diatonic chords work, a chart for all 12 keys, and the actual steps for arranging the seven into a chord progression — all with sound, so you can check as you go.
What Are Diatonic Chords?
Diatonic chords are chords built using only the notes of that key’s scale.
The C major scale is the seven notes C, D, E, F, G, A, B. Building on each of these seven notes and stacking two more notes a third apart gives you seven chords.
For example, starting from C: C → (skip D) → E → (skip F) → G. That gives “C, E, G” = C. Next, starting from D: “D, F, A” = Dm. Not a single black key is used.
| Degree | Chord | Notes |
|---|---|---|
| Ⅰ | C | C・E・G |
| ⅱ | Dm | D・F・A |
| ⅲ | Em | E・G・B |
| Ⅳ | F | F・A・C |
| Ⅴ | G | G・B・D |
| ⅵ | Am | A・C・E |
| ⅶ° | Bdim | B・D・F |
The seventh, Bdim, sounds a bit unstable and rarely appears on its own in real songs. Learning the other six is plenty to start.
Why Only Seven?
A song has a “key,” and the notes used in that key are fixed in advance. In C major, that’s the seven white keys.
If the notes are fixed, the chords you can build from them are automatically fixed too. That’s why there are only seven.
That doesn’t mean you can never use anything outside these seven, of course. But the moment you step outside the seven, the ear notices something has changed. That’s what modulation and borrowed chords really are.
Diatonic Chords for All 12 Keys
Here are all 12 keys laid out. The top 6 rows are sharp keys, the bottom 6 are flat keys.
| Key | Ⅰ | ⅱ | ⅲ | Ⅳ | Ⅴ | ⅵ | ⅶ° |
|---|---|---|---|---|---|---|---|
| C major (C) | C | Dm | Em | F | G | Am | Bdim |
| G major (G) | G | Am | Bm | C | D | Em | F♯dim |
| D major (D) | D | Em | F♯m | G | A | Bm | C♯dim |
| A major (A) | A | Bm | C♯m | D | E | F♯m | G♯dim |
| E major (E) | E | F♯m | G♯m | A | B | C♯m | D♯dim |
| B major (B) | B | C♯m | D♯m | E | F♯ | G♯m | A♯dim |
| G♭ major (G♭) | G♭ | A♭m | B♭m | C♭ | D♭ | E♭m | Fdim |
| D♭ major (D♭) | D♭ | E♭m | Fm | G♭ | A♭ | B♭m | Cdim |
| A♭ major (A♭) | A♭ | B♭m | Cm | D♭ | E♭ | Fm | Gdim |
| E♭ major (E♭) | E♭ | Fm | Gm | A♭ | B♭ | Cm | Ddim |
| B♭ major (B♭) | B♭ | Cm | Dm | E♭ | F | Gm | Adim |
| F major (F) | F | Gm | Am | B♭ | C | Dm | Edim |
It looks like a lot, but you don’t need to memorize it. Press a key in the tool above and the seven appear instantly.
What matters more is noticing that the pattern is the same in every key: the 1st, 4th, and 5th are major, the 2nd, 3rd, and 6th are minor, and the 7th is dim. That never changes, whatever the key.
Learning It by Scale Degree (Roman Numerals)
If the pattern is always the same, it pays to learn it by position rather than by chord name. Scale degrees (Roman numerals) are the notation for that.
| Degree | Type | C major | G major | E♭ major |
|---|---|---|---|---|
| Ⅰ | Major | C | G | E♭ |
| ⅱ | Minor | Dm | Am | Fm |
| ⅲ | Minor | Em | Bm | Gm |
| Ⅳ | Major | F | C | A♭ |
| Ⅴ | Major | G | D | B♭ |
| ⅵ | Minor | Am | Em | Cm |
| ⅶ° | Diminished | Bdim | F♯dim | Ddim |
Capital letters mean major, lowercase mean minor. Written this way, the same notation works regardless of key.
For example, the progression “Ⅰ→Ⅴ→ⅵ→Ⅳ” is C→G→Am→F in C major, and G→D→Em→C in G major. The shape stays the same — only the location moves.
Switch keys in the tool above and the chords you’ve placed transpose right along with it. Try listening for yourself — the relationship between the degrees never changes.
The Seven Have Three Roles
The seven chords fall into three groups by role. Once this clicks, you can decide the order yourself.
| Role | Chords (C major) | Feel |
|---|---|---|
| Tonic (home) | Ⅰ・ⅲ・ⅵ C・Em・Am | Settled. Goes at the start and end |
| Subdominant (going out) | Ⅳ・ⅱ F・Dm | Drifts away. Adds movement |
| Dominant (heading home) | Ⅴ・ⅶ° G・Bdim | Pulls strongly. Makes you want to go home |
Tonic → Subdominant → Dominant → Tonic. That’s the most basic flow of all. In C major, that’s C→F→G→C.
Press ▶ and you’ll hear C→F→G→C (Ⅰ–Ⅳ–Ⅴ–Ⅰ).
The moment it lands back on C, you should feel like it properly resolved. Creating that “back home” feeling is the Dominant’s (G’s) job.
Building a Chord Progression from Diatonic Chords
Once you know the seven, all that’s left is arranging them. There’s no need to overthink it.
Step 1: Start on Ⅰ, End on Ⅰ
Start by thinking in 4 bars. Make bar 1 and bar 4 Ⅰ (C in C major). That alone gives you “one complete unit.”
Step 2: Put Ⅴ in Bar 3
Placing Ⅴ (G) right before the ending strengthens the pull back to the final Ⅰ. That gives you the shape Ⅰ・?・Ⅴ・Ⅰ.
Step 3: Put Whatever You Like in Bar 2
Try putting ⅵ (Am), Ⅳ (F), or ⅱ (Dm) in the remaining bar 2. Changing just this one spot changes the whole feel of the piece.
With ⅵ (Am) in bar 2. A touch more wistful.
Make bar 2 an Ⅳ (F) instead and it opens up brighter.
The same Ⅰ–Ⅳ–Ⅴ–Ⅰ, arpeggiated. Starts to sound like real accompaniment.
In the tool above, press bar 2 and swap in a different chord. You’ll see how much the impression shifts from changing just one.
Even the Classic Progressions Live Inside These Seven
Written by scale degree, some well-known chord progressions look like this.
| Progression | Degrees | In C Major |
|---|---|---|
| Canon progression | Ⅰ–Ⅴ–ⅵ–ⅲ–Ⅳ–Ⅰ–Ⅳ–Ⅴ | C→G→Am→Em→F→C→F→G |
| Royal Road progression | Ⅳ–Ⅴ–ⅲ–ⅵ | F→G→Em→Am |
| Komuro progression | ⅵ–Ⅳ–Ⅴ–Ⅰ | Am→F→G→C |
| Circle progression | Ⅰ–ⅵ–ⅱ–Ⅴ | C→Am→Dm→G |
In other words, knowing the seven lets you build every one of the classic progressions. A detailed walkthrough of each is in Piano Chord Progressions Explained: 5 Classic Patterns with Sound.
Seventh-Chord Diatonic Chords
Stack one more note a third apart on top of the triad and you get a seventh chord. It’s the sound heard often in jazz and more sophisticated-sounding songs.
| Degree | Chord (C major) | Role |
|---|---|---|
| Ⅰmaj7 | CM7 | Tonic |
| ⅱm7 | Dm7 | Subdominant |
| ⅲm7 | Em7 | Tonic |
| Ⅳmaj7 | FM7 | Subdominant |
| Ⅴ7 | G7 | Dominant |
| ⅵm7 | Am7 | Tonic |
| ⅶm7♭5 | Bm7♭5 | Dominant |
What’s worth noticing is that only Ⅴ becomes a “7” (G7). Everything else is M7 or m7, but the fifth is the odd one out.
This G7 is the chord that pulls hardest toward Ⅰ. Jazz’s classic “two-five-one” (Dm7→G7→CM7) comes from exactly this.
The triads swapped out for seventh chords (CM7→FM7→G7→CM7).
Compare it against the triad version, C→F→G→C, and even though it’s the same progression, it sounds noticeably more mature. Pick M7, m7, or 7 from “choose chord” in the tool above and you can build your own.
For more on two-five, see Two-Five (Ⅱ–Ⅴ–Ⅰ) Explained.
Diatonic Chords in Minor Keys
Minor keys have diatonic chords too. But there’s no need to relearn anything.
The notes used in A minor are A, B, C, D, E, F, G — the exact same seven notes as C major (this is called a relative key). Which means the seven chords you get are the same too.
The only difference is which one feels like “home.” In C major, C is home. In A minor, Am is home.
| Home (Tonic) | Seven Chords | |
|---|---|---|
| C major | C | C・Dm・Em・F・G・Am・Bdim |
| A minor | Am | Am・Bdim・C・Dm・Em・F・G |
So if you want to work in A minor with the tool, pick the relative C major and just start arranging from Am — that works as-is.
That said, in real songs, Em is often changed to E (or E7) to strengthen the dominant pull. Raising G to G♯, this is what’s called the harmonic minor scale. This E sits outside the seven, but it’s completely normal in minor keys.
You can check which key pairs with which minor key at All-Key Scale Chart.
Frequently Asked Questions
What are diatonic chords?
They’re the seven chords built using only the notes of that key’s scale. In C major, that’s the seven chords you can build using just the white keys: C, Dm, Em, F, G, Am, Bdim. Most of the chords used in a song fall within this set.
Do I have to memorize all seven?
No. Four chords — Ⅰ, Ⅳ, Ⅴ, and ⅵ (C, F, G, and Am in C major) — will get you through most pop songs. ⅶ° (Bdim) is rarely used on its own, so it’s fine to leave for last.
Am I not allowed to use anything besides diatonic chords?
You can. Chords outside the seven are called borrowed chords or secondary dominants, and they’re used to add variety to a piece.
That said, the order matters — first get comfortable writing within the seven alone. Without a baseline, you can’t notice when you’ve stepped outside it.
What if I don’t know the key?
Check the key signature (the number of sharps or flats) on the score. One sharp is G major, one flat is F major, and so on. The method for telling them apart is explained in How to Learn and Use the Circle of Fifths.
Why are the 2nd, 3rd, and 6th minor?
Because the spacing between the scale notes isn’t even. The gap between C and D is a whole step, but between E and F it’s only a half step. That difference changes the shape of the chords you stack.
The result is the same pattern in every key: “1, 4, 5 are major; 2, 3, 6 are minor; 7 is dim.” That pattern is all you need to memorize.
Related Reading
- Piano Chord Progressions Explained: 5 Classic Patterns｜The classic shapes that come from arranging the seven
- Piano Chord Chart｜For looking up how to play each individual chord
- How to Learn and Use the Circle of Fifths｜See at a glance how the seven chords sit in three columns of the circle
- Canon progression / Royal Road progression / Komuro progression｜Detailed breakdowns of the three classics
- All-Key Scale Chart｜Each key’s scale and its relative-key pairing
Summary
- Only seven chords are used in a given key. In C major, the seven you can build using white keys
- The pattern is the same in every key: 1, 4, 5 are major; 2, 3, 6 are minor; 7 is dim
- So learn it by scale degree (Ⅰ・ⅱ・ⅲ…). The shape stays the same even when the key changes
- The trick to arranging them: start on Ⅰ, end on Ⅰ, with Ⅴ right before the end
- A minor key shares the same seven as its relative major. Only “home” is different
Learning the seven as a group gets you to writing music far faster than memorizing chords one at a time.
The tool above doesn’t save anything, so try it as many times as you like. Press the seven buttons however you want, and once you find an arrangement you like, use the share button to grab the URL.
