Chords in a Major Key

Every major key contains seven basic diatonic triads: one chord built on each scale degree.

The pattern is always the same:

I–ii–iii–IV–V–vi–vii°

In C major, this gives:

C–Dm–Em–F–G–Am–Bdim

In G major:

G–Am–Bm–C–D–Em–F♯dim

The chord names change, but the order of chord qualities stays the same:

major–minor–minor–major–major–minor–diminished

This pattern helps you build chords in any major key, transpose progressions, and understand how harmony moves.

Where major-key chords come from

Take C major:

C–D–E–F–G–A–B

If you build a triad on each degree by taking every other scale note, you get:

C–E–G   = C
D–F–A   = Dm
E–G–B   = Em
F–A–C   = F
G–B–D   = G
A–C–E   = Am
B–D–F   = Bdim

This is how the diatonic chords of a key are built. The full process is explained in What Are Diatonic Chords?.

The chord map of a major key

The Roman numeral shows the scale degree of the chord.

The letter case shows the chord quality:

I  = major chord
ii = minor chord

The ° symbol marks a diminished triad:

vii°

Three functional areas

For practice, it is useful to divide the chords of a major key into three areas.

The simplest harmonic route is:

stability → motion → tension → return

For example:

I → IV → V → I
C → F  → G → C

This is not a strict rule. A chord’s actual role depends on context, bass movement, inversion, and the surrounding chords. Still, this map helps explain why some chords feel stable while others seem to require continuation.

The primary chords: I, IV, and V

The three major chords in a major key are built on the first, fourth, and fifth degrees:

I, IV, V

In C major:

C, F, G

They form the basic harmonic framework:

I → IV → V → I
C → F  → G → C

This progression clearly shows the basic route:

• I — center;
• IV — movement away from the center;
• V — tension;
• I — return.

This logic appears in countless songs, folk harmonies, blues forms, and practice examples.

Predominant chords: ii and IV

The chords ii and IV often prepare the dominant.

In C major:

ii = Dm
IV = F

They are similar in pitch content:

Dm = D–F–A
F  = F–A–C

They share two notes: F and A.

That is why both chords can lead to V, even though they sound different:

IV → V
F  → G

ii → V
Dm → G

The ii–V–I progression shows this motion very clearly:

preparation → tension → resolution

In C major:

Dm → G → C

Dominant chords: V and vii°

The main dominant chord in a major key is built on the fifth degree.

In C major:

V = G

It contains the leading tone B:

G–B–D

B lies a semitone below the tonic C and pulls toward it:

B → C
7 → 1

That is why this movement:

V → I
G → C

sounds like a strong return.

The vii° chord also belongs to the dominant area.

In C major:

vii° = Bdim
Bdim = B–D–F

It contains two strong tendencies:

B → C
F → E

So vii° can resolve to I:

Bdim → C
vii° → I

A diminished chord sounds tense not because it is wrong, but because its job is to create motion.

Minor chords inside a major key: vi and iii

A major key contains three minor triads:

ii, iii, vi

The ii chord usually prepares the dominant. The iii and vi chords are closer to the tonic area.

In C major:

I   = C
vi  = Am
iii = Em

The vi chord shares two notes with I:

C  = C–E–G
Am = A–C–E

That makes vi sound close to the tonic, but with a minor color.

The iii chord also shares notes with both I and V:

C  = C–E–G
G  = G–B–D
Em = E–G–B

Because of this, iii often works as a connecting chord. It is weaker than I, IV, or V, but useful for smooth motion.

For example:

I → iii → vi
C → Em  → Am

The common I–V–vi–IV progression

One of the most common major-key progressions is:

I → V → vi → IV

In C major:

C → G → Am → F

After V, the ear often expects a return to I, but this progression moves to vi instead:

V → vi
G → Am

This motion does not fully close the phrase. The progression keeps looping and can easily return to the beginning.

The same progression with a different starting point

If you reorder the same chords, the beginning feels different.

vi → IV → I → V
Am → F → C → G

The chord set is the same, but the first point of support is now minor. That changes the color of the opening bars.

The key is still C major. The first chord of a progression is not always the tonic.

How to transpose progressions

The major-key pattern stays the same in every key:

I–ii–iii–IV–V–vi–vii°

To transpose a progression, keep the Roman numerals and replace the chord names.

For example:

I–V–vi–IV

In C major:

C–G–Am–F

In D major:

D–A–Bm–G

The relationships stay the same. Only the pitch level changes.

This is useful when you need a key that fits a voice, another instrument, or more comfortable fingerings.

How to build the chords of any major key

The process is simple.

1. Write the major scale

For example, D major:

D–E–F♯–G–A–B–C♯

2. Apply the pattern

I–ii–iii–IV–V–vi–vii°

3. Get the chords

You do not need to recheck every triad quality from scratch. Learn the scale notes and the general order:

major–minor–minor–major–major–minor–diminished

How melody relates to the chords

All diatonic chords in a major key are built from the same scale.

In C major, the shared note collection is:

C–D–E–F–G–A–B

But the same note can sound different over different chords.

For example, B:

• forms a major seventh above C;
• belongs to Em;
• is the third of G;
• belongs to Bdim.

The scale shows the available note collection. The current chord shows the role a note plays at that moment.

How Six Strings App can help

In Harmony, you can choose any major key and see its scale, degrees, and chords.

Compare C major, G major, and D major. The chord names change, but the pattern stays the same:

I–ii–iii–IV–V–vi–vii°

In the Song Builder, you can create progressions such as:

I–IV–V–I
I–V–vi–IV
vi–IV–I–V
ii–V–I

Then change the key and compare the result.

In Chords, Arpeggios, and Scales, you can check the notes of each chord and find practical fingerings.

Five-minute exercise

1. Write the pattern

I–ii–iii–IV–V–vi–vii°

Add the chord qualities:

major–minor–minor–major–major–minor–diminished

2. Build the chords of D major

D–Em–F♯m–G–A–Bm–C♯dim

3. Play the primary chords

I–IV–V–I
D–G–A–D

Listen for the movement from center to tension and back.

4. Add minor chords

Play:

I–V–vi–IV
D–A–Bm–G

Then:

vi–IV–I–V
Bm–G–D–A

Compare the beginning of the two progressions.

5. Transpose the pattern

Move I–V–vi–IV to A major:

A–E–F♯m–D

Common mistakes

Memorizing only the chords of C major. It is better to learn the quality pattern and apply it to any major scale.

Confusing degree and chord quality. The numeral shows the chord’s position in the key. Letter case and the ° sign show its quality.

Treating all chords as equally stable. I establishes the center, V and vii° create tension, and ii and IV often prepare the dominant.

Assuming the first chord is the tonic. A progression can start on vi, ii, or IV and still remain in a major key.

Avoiding the diminished chord. The tension of vii° is its function, not a mistake.

Treating the formula as a ban on other chords. Non-diatonic and borrowed chords can expand the harmony.

Identifying function only by Roman numeral. The real role depends on context, bass movement, inversion, and neighboring chords.

What to study next

• What Is a Cadence? — ways to end musical phrases.
• Chords in a Minor Key — chords from natural, harmonic, and melodic minor.
• What Is Chord Function? — the role of a chord inside a key.
• Tonic, Subdominant, and Dominant — the three main harmonic functions.
• What Are Diatonic Chords? — how chords are built from scale notes.
• Scale Degrees in a Key — how notes and chords relate to the tonic.
• How Are Triads Built? — the interval structure of chords.
• Harmony — chords, cadences, and modulations in a selected key.

Short summary

In every major key, the diatonic triads follow one pattern:

I–ii–iii–IV–V–vi–vii°

I establishes the center. ii and IV prepare motion. V and vii° lead back to the tonic. iii and vi expand the tonic area and change the color of a progression.

Once you know this map, you can build the chords of any major key, transpose progressions, and understand harmonic motion without relying on specific chord names.