> **From theory:** chords live on [/theory/western/#chords](/theory/western/#chords). This page builds them from the [major scale](major-scale.md).

# How chords are built

> Interactive page: [`building-chords.html`](building-chords.html). Every **Hear** button on that page plays the chord.

Leave the right hand where the scale left it: thumb on middle C, then D, E, F, G. Play only the thumb, the middle finger, and the pinky — C, E, and G — together. That is a chord. The scale was the notes in a row. A song is those notes one at a time, over chords that change.

## Three notes, three jobs

Those three fingers are degrees **1, 3, and 5**: **C**, **E**, and **G**. Fingers 2 and 4 stay up. Three notes built this way are a **triad**. It is named for its root, so this is **C major** — major because note 3 is the major scale's own 3rd.

- **Root (1)** names the chord. C E G is a C chord because C is note 1 of the recipe, even when another chord tone sits in the bass.
- **Third (3)** is the color. Lower E to E♭ and the chord turns from bright to dark.
- **Fifth (5)** is the support. It stays put in ordinary major and minor chords.

A melody leans on the chord underneath it. Over C, the strong notes to land on are C, E, and G. Over F, they are F, A, and C.

## Count the half steps

From C on the chromatic ladder:

- **4** half steps lands on E, a **major third**.
- **3** half steps lands on E♭, a **minor third**.
- **7** half steps lands on G, a **perfect fifth**. Major and minor chords both use it.
- **6** half steps lands on G♭. The fifth has shrunk.
- **8** half steps lands on G♯. The fifth has grown.

A triad is two thirds stacked:

| Quality | Thirds | On C |
|---------|--------|------|
| Major | 4, then 3 | C E G |
| Minor | 3, then 4 | C E♭ G |
| Diminished | 3, then 3 | C E♭ G♭ |
| Augmented | 4, then 4 | C E G♯ |

**Minor** is major with the 3rd lowered one half step. **Diminished** lowers the 3rd and the 5th. **Augmented** keeps the major 3rd and raises the 5th. Songs live mostly on major and minor. Diminished appears once in every major key, on degree 7.

The symbol spells the recipe. **C** is major. **Cm** is minor. **C°** (or Cdim) is diminished. **C+** (or Caug) is augmented. The letter is the root.

## Every other note

From C, skip D, take E; skip F, take G. Keep stacking:

```
C  E  G  B  D  F  A
```

Three notes is the triad. Four notes, through B, is a seventh chord. The catalog of chord types is this stack with a degree raised or lowered.

Some chords leave the 3rd out, so they are neither major nor minor. **C F G** is **Csus4**. **C D G** is **Csus2**. **C G** is a power chord.

## The seven chords in the key

Build a triad on every degree of C major, using only scale notes. The scale decides the quality.

| Degree | Notes | 3rd · 5th (half steps) | Chord |
|--------|-------|------------------------|-------|
| 1 C | C E G | 4 · 7 | **C** |
| 2 D | D F A | 3 · 7 | **Dm** |
| 3 E | E G B | 3 · 7 | **Em** |
| 4 F | F A C | 4 · 7 | **F** |
| 5 G | G B D | 4 · 7 | **G** |
| 6 A | A C E | 3 · 7 | **Am** |
| 7 B | B D F | 3 · 6 | **B°** |

**4 · 7** is major. **3 · 7** is minor. **3 · 6** is diminished.

A major chord on D would be **D F♯ A**. C major has F, three half steps above D, so the chord is **D F A**, minor. The same test fills the rest of the table.

In every major key the seven chords come out **major, minor, minor, major, major, minor, diminished**. Degrees **1, 4, and 5** are major. Degrees **2, 3, and 6** are minor. Degree **7** is diminished.

## What each chord is for

Roman numerals name the jobs. A capital numeral is major. A small numeral is minor. The circle marks diminished.

| | In C | Job |
|--|------|-----|
| **I** | C | Home. The tonic. |
| **IV** | F | A step away. C is in both chords. The subdominant. |
| **V** | G | The pull home. B, its 3rd, is one half step under C — the leading tone. The dominant. |
| **vi** | Am | A darker home. The relative minor. |
| **ii** | Dm | The path into V. D belongs to both Dm and G. |
| **iii** | Em | Home, softened. E and G are already inside C. |
| **vii°** | B° | Tense. It also holds the leading tone. Beginner charts usually skip it. |

**I, IV, and V** are the primary chords. **ii, iii, and vi** stay in the key and add color.

Shared notes, which are the ones to keep under the hand:

| Move | In C | Note that stays |
|------|------|-----------------|
| I → IV | C → F | C |
| I → V | C → G | G |
| I → vi | C → Am | C and E |
| I → iii | C → Em | E and G |
| ii → V | Dm → G | D |
| V → I | G → C | G stays; B rises to C |

C and Dm share nothing, so I → ii is a bigger step than I → vi.

## The same family in G

G major is **G A B C D E F♯ G**. The qualities come out in the same order:

| I | ii | iii | IV | V | vi | vii° |
|---|----|-----|----|---|----|------|
| **G** | Am | Bm | C | **D** | Em | F♯° |

F♯ is the 3rd of the V chord, **D F♯ A**. The black key in the G major scale is the note that makes the dominant pull home. **I–V–vi–IV** in C is C–G–Am–F; in G it is G–D–Em–C. Every key's family is on the [cheat-sheet](chord-cheatsheet.md).

## How a song moves

| Loop | In C | What you are hearing |
|------|------|----------------------|
| **I–V–vi–IV** | C G Am F | Home, the pull, the darker home, a step away |
| **I–IV–V–I** | C F G C | The three primary chords, out and back |
| **ii–V–I** | Dm G C | ii hands the phrase to V, and V resolves |
| **I–vi–IV–V** | C Am F G | Home, softened, then IV–V returns |

A **12-bar blues** is I for four bars, IV for two, I for two, then V–IV–I–I. Play one chord per bar, metronome near 60. Real tunes are on [Play along](songs.md).

## The same chord, three shapes

**C E G**, **E G C**, and **G C E** are all C major. The lowest note changed. That is an **inversion**. The slash names the bass.

| Shape | Low to high | Bass | Symbol |
|-------|-------------|------|--------|
| Root position | C E G | C | **C** |
| First inversion | E G C | E | **C/E** |
| Second inversion | G C E | G | **C/G** |

Right hand, root position: thumb (**1**) on C, **3** on E, **5** on G. Left hand an octave lower: **5**, **3**, **1**, or the root alone. **G/B** is a G chord with the leading tone in the bass, already on its way to C.

## One more third

| Chord | Notes | The 7th |
|-------|-------|---------|
| **Cmaj7** | C E G B | The scale's own 7th. Warm, and content on I. |
| **G7** | G B D F | V, plus a lowered 7th. B rises to C, F falls to E. |
| **Am7** | A C E G | vi, plus its 7th. |
| **Dm7** | D F A C | ii, plus its 7th. Still walks into G7. |

Sixths, ninths, and altered notes are the same stack with one more edit. Take one apart the same way: find the root, stack the thirds, and see which degree moved.

## Play it before you turn the page

1. C alone, then C E G. Name root, third, fifth.
2. The seven chords of C, saying I through vii°.
3. **C–G–Am–F**, one chord per bar, then the root in the left hand.
4. The same jobs in G: **G–D–Em–C**.

Next: the [minor scale](minor-scale.md), which stretches that lowered 3rd into seven notes.

## Other chord types

Suspensions, sixths, ninths, and altered notes are gathered under **Chords & harmony**. [Chord types](chord-types.md) is one recipe per row. The seven chords of every key are on the [cheat-sheet](chord-cheatsheet.md), and every spelling in all twelve keys is in the [dictionary](chord-dictionary.md).