Free online chord finder

A chord is what you hear when several notes sound at once, and it is the harmony that a melody sits on top of. Nearly all the chords in popular music are built the same way — by stacking notes from a scale in a regular pattern — so once you see how that stacking works, chord names like Am7 or Csus4 stop being codes to memorise and start describing exactly what your fingers are doing. Below is how chords are built, what the common types are, and how to read them on the keyboard.

What a chord is

The simplest full chord is the triad: three notes built by starting on a root, skipping a note, taking the next, skipping again, and taking one more. On the keyboard that comes out as the root, the note two white keys up, and the note two white keys above that — C, E, G is a C major chord. The gaps you skip are thirds, and stacking thirds is the engine behind almost every chord. The root gives the chord its letter name; what you stack on top gives it its type.

Major and minor triads

The difference between a major and a minor chord is a single note: the middle one. A major triad has a larger gap (a major third) on the bottom and a smaller one on top, which sounds bright and settled. A minor triad flips that — the smaller gap is on the bottom — so the middle note drops a half step and the chord sounds darker. C, E, G is C major; C, E flat, G is C minor. Because only one note moves, switching a chord between major and minor is one of the most useful moves you can learn, and seeing it here makes the shift obvious.

Diminished and augmented triads

Two more triads come from squeezing or stretching the stack. A diminished triad uses two small (minor) thirds, so the top note sits lower than in a minor chord; it sounds tense and unstable and wants to resolve. An augmented triad uses two large (major) thirds, so the top note sits higher than in a major chord, giving a strange, suspended quality. Neither is as common as major and minor, but both turn up as colour and as stepping-stones between other chords.

Seventh chords

Add one more note a third above the triad and you have a seventh chord, which sounds fuller and more restless than a plain triad. The three you will meet most are the dominant seventh (a major triad plus a lowered seventh), which drives the pull back to a key’s home chord; the major seventh (a major triad plus the note a half step below the octave), which sounds warm and jazzy; and the minor seventh (a minor triad plus a lowered seventh), which is mellow and common in soul and pop. The finder spells each one out so you can see exactly which note the seventh adds.

Suspended and added-note chords

Not every chord is built purely from thirds. A suspended chord replaces the middle note with the note just above or below it — sus4 uses the fourth, sus2 uses the second — leaving the chord unresolved until that note moves. Added-note chords keep the triad but drop in an extra tone, like the add9 that gives so much modern pop its open, ringing sound. These are easy to hear and easy to see when the notes light up on the keys.

Where chords come from

Chords are not random stacks; they grow out of scales. Build a triad on each note of a scale, using only that scale’s notes, and you get the chords that belong to its key — which is why a song in one key keeps returning to the same handful of chords. The scale finder shows the parent scale a chord is drawn from, and the interval finder breaks a chord down into the individual distances between its notes. Every chord you find here can be played in full on the virtual piano.

Extended chords: ninths, elevenths, thirteenths

Keep stacking thirds above a seventh chord and you reach the extended chords — the ninth, eleventh, and thirteenth. Each adds another note further up the scale, and each adds richness and a jazzier, less settled colour. A ninth chord is a seventh chord with the note an octave-and-a-second above the root added on top; elevenths and thirteenths go further still. They can sound complex, but the logic never changes: it is always thirds stacked on a root, and the finder spells out every note so you can see how far the stack has grown.

How chords work in a key

Within a key, the chords built on each scale degree take on roles, usually written as roman numerals: the chord on the first degree is the I, on the fourth the IV, on the fifth the V, and so on, with capitals for major chords and lowercase for minor. Three of these carry most of the weight — the tonic (I) that feels like home, the subdominant (IV) that moves away, and the dominant (V) that pulls strongly back to the tonic. That pull is why a V chord so often leads to a I at the end of a phrase, and why a dominant seventh, which sharpens the tension, is such a common signpost that a resolution is coming.

Common chord progressions

Because those roles are so consistent, a handful of progressions turn up again and again. The I–V–vi–IV progression carries an enormous number of pop songs; the ii–V–I is the backbone of jazz; and the twelve-bar blues cycles through I, IV, and V in a fixed pattern. Take three or four chords that belong to one key — the chord finder shows which notes they share — and playing them in a loop is the fastest way to hear how a progression creates momentum and release.

Slash chords and the bass note

Sometimes a chord is written with a second letter after a slash, like C/E, which means play a C chord but put E in the bass. The chord is still C major; only the lowest note has changed, often to make a smoother bass line from one chord to the next. It is a close cousin of inversion, and a reminder that the lowest note colours a chord’s feel even when the notes themselves stay the same.

Inversions: the same chord, reordered

A chord keeps its identity no matter which of its notes is on the bottom. Move the root up an octave so the third sits lowest and you have the same chord in first inversion; it sounds a little different and is often easier to move between chords smoothly, but C, E, G and E, G, C are both C major. Recognising a chord regardless of its order is a skill worth building, and the chord ear trainer drills exactly that by ear.

Reading chord symbols

Chord names are a compact code, and it is worth learning to read it. A plain letter means a major chord, so C is C major. A lowercase m or “min” means minor: Cm. A number adds a seventh or an extension: C7 is a dominant seventh, Cmaj7 a major seventh, Cm7 a minor seventh. Shortened words cover the rest — dim for diminished, aug for augmented, sus for suspended, add for an added note. Once you can read the symbol you can read the chord straight off a chart, and the finder’s named output is a good way to connect each symbol to the notes it stands for.

Voicing: spacing the same chord

A chord is a set of notes, not a fixed shape, so the same chord can be spread across the keyboard in many ways — close together in one hand, or spaced widely between two. That arrangement is called the voicing, and it changes how full or transparent a chord sounds without changing which chord it is. Players choose voicings to keep a smooth line from one chord to the next and to avoid a muddy cluster low down. The finder shows a chord in its plainest position; once you know the notes, you are free to spread them however sounds best.

Reading it on the keyboard

Pick a root and a chord type and the chord tones light up across the central octave, with the root in a stronger colour and the notes named beside the chord’s full name. Use the flats toggle to read the chord the way its key is normally written. If a note name is unfamiliar, the note finder shows where it sits all over the keyboard.

Ways to practise with it

• Play a chord one note at a time from the bottom up, then all together, so you hear how the stack builds.
• Flip a chord between major and minor and listen for the single note that changes the whole colour.
• Take three or four chords from the same key and play them in a loop to feel how a progression moves.