Random Chord Generator

A chord is a stack of thirds

Strip away everything mysterious about chords and you are left with one simple building instruction: take a note, skip a note, take a note, skip a note, take a note.

That is a chord. Three notes, each a third apart, which is why theorists call it stacking in thirds. On a keyboard it means playing every other white key: C, skip D, E, skip F, G. Those three notes, C E G, are a C major chord, and the same skipping pattern starting on any note gives you a chord rooted on that note.

The three notes even have plain names. The bottom one is the root, and it is the note the whole chord is named after. The middle one is the third, because it sits a third above the root. The top one is the fifth, a fifth above the root. Root, third, fifth. A three-note chord like this is called a triad, and it is the foundation of nearly all the harmony you have ever heard.

Everything else, every complicated-looking chord symbol in this generator, is a variation on that snowman of stacked notes.

The middle note decides the mood

Here is the single most useful thing to know about chords, and it explains that happy-versus-sad feeling everyone can hear but few can name.

The mood of a basic chord lives almost entirely in the middle note, the third. Move it by the smallest possible amount, a single semitone, and the chord flips from major to minor, from bright to dark, from happy to sad. The root stays. The fifth stays. Only the third moves, and the entire emotional colour changes.

This is why the two most common chords are called major and minor, and why they feel like opposites. A major chord has its third sitting high; a minor chord has it dropped down a semitone. That tiny difference is one of the most powerful effects in all of music, and it is controlled by a single note moving the smallest distance the system allows.

Two rarer triads push the same note further. Squeeze both intervals and you get a diminished chord, tense and unstable, the sound of suspense. Stretch them both and you get an augmented chord, strange and dreamlike, the sound of something not quite real. Four moods, four triads, all decided by where the inner notes sit.

You can hear these characters described the same way everywhere: major sounds happy, minor sad, diminished scary, augmented mysterious. It is worth playing all four and feeling it for yourself.

Reading the shorthand

The symbols in this generator look cryptic until you learn the code, and then they read instantly. The whole system is a compact shorthand for the stacking instructions above.

A capital letter on its own, like A, means a major triad on that root. That is the default, so it needs no extra mark. A small m, as in Am, means minor, the darker version with the lowered third. Adim means diminished, Aaug means augmented. Those four cover the basic triads.

Then come the modifiers. A number like A7 adds a note above the triad. Amaj7 specifies which kind of added note. Asus means suspended, where the third, the mood note, is replaced by a neighbour, leaving the chord hanging and unresolved. Aadd9 reaches up to add a note from higher in the stack. A5 is the bare bones, just root and fifth with no third at all, which is why it is neither happy nor sad and why rock guitarists love it.

None of these are arbitrary. Each symbol names exactly which notes to stack and which to alter. Once the code clicks, a chord symbol is a complete recipe you can read at a glance.

Adding a fourth note

Keep stacking. If a triad is three notes a third apart, then adding one more third on top gives you a four-note chord, and the new note sits a seventh above the root. These are called seventh chords, and they are where harmony starts to get rich.

The difference in feel is immediate. A plain triad sounds settled and stable. Add the seventh and the chord gains a slight tension, a lean, a sense that it wants to move somewhere. That restlessness is enormously useful, because music is largely about tension and release, and the seventh chord is a reliable way to create the tension that a resolution then satisfies.

This is why so much jazz, soul and blues is built on sevenths rather than plain triads. The added note makes every chord a little unstable, a little hungry, and stringing those hungers together is what gives the music its restless, flowing quality. A whole style can turn on the decision to stack one more third.

The list here includes several of these, which is a good reminder that a chord is not a fixed object but a stack you can keep building.

Using a random chord

Play it, then name what you hear. Before analysing the symbol, sound the chord out and decide what mood it has. Training your ear to match the feeling to the name is the whole skill.

Build progressions from it. Take the chord as a starting point and find two or three others that sound good moving to and from it. That is songwriting in miniature.

Use it as an ear-training drill. Generate a chord, guess its quality by sound alone, then check the symbol. Major, minor, diminished, augmented, done repeatedly, sharpens your ear fast.

Try the same chord in different positions. Rearrange the three notes so a different one is on the bottom. The chord stays the same chord but takes on a subtly different colour.

Follow it into a key. Any chord belongs to several keys at once. Working out which keys a chord fits is a direct path into understanding the musical keys it lives in.

How this chord list works

The chords here are drawn from a list our team assembled by hand, covering the common triads and their extensions across all twelve roots. One is chosen at random each time. It runs on your own device, and nothing you type is sent anywhere.

Questions people ask about chords

What exactly is a chord?

Most simply, three or more notes sounded together. The most basic chord is a triad, built by stacking notes a third apart, giving a root, a third and a fifth. Nearly all common harmony is built from this stacking pattern.

What makes a chord major or minor?

The middle note, the third. A major chord has it a semitone higher, a minor chord a semitone lower. That single note, moved the smallest possible distance, is what creates the familiar bright-versus-dark, happy-versus-sad difference.

How do I read chord symbols?

The capital letter is the root note. On its own it means major; a small m means minor; dim and aug are the two other triads. Numbers and words like 7, sus and add9 tell you which extra notes to stack or alter.

What is a seventh chord?

A triad with one more note stacked on top, a third above the fifth, landing a seventh above the root. It adds a pleasant tension that makes the chord feel like it wants to move, which is why it is central to jazz, blues and soul.

What does sus mean?

Suspended. The third, the note that carries the mood, is replaced by a neighbouring note, so the chord is neither major nor minor. It sounds open and unresolved, as though waiting to settle back onto a normal chord.

References

1. Triad (music). https://en.wikipedia.org/wiki/Triad_(music)
2. Triads. Open Music Theory. https://viva.pressbooks.pub/openmusictheory/chapter/triads/