Tools
Chord Builder
Choose a root note and a chord type, from simple major and minor triads to extended chords like 9, 11 and 13. The chord builder shows the notes, the formula and how to play it on guitar, ukulele, piano and the staff, and lets you hear it. Everything works in your browser; no app, no sign-up.
How to use it
- Select the root note (C, C#, Db, D...).
- Select the chord type, for example maj7, m7 or sus4.
- Choose the instrument view: guitar, ukulele, piano or staff.
- Press play to hear the chord, strummed or as an arpeggio.
- Compare voicings and change the root to transpose the same shape.
How chords are built
Every chord is a set of notes taken from a root using a formula of intervals. A major triad is root, major third and perfect fifth (1 3 5). A minor triad lowers the third (1 b3 5). Seventh chords add a fourth note: a major seventh chord is 1 3 5 7, a dominant seventh is 1 3 5 b7, a minor seventh is 1 b3 5 b7. Extended chords keep stacking thirds: 9, 11 and 13.
The chord builder shows this formula next to the actual note names, so you can see why a chord sounds the way it does. Compare C major with C minor: only one note moves, by a half step.
Useful ways to practise with it
- Learn chord families: keep the root fixed and step through maj, m, 7, maj7, m7 and m7b5. Listen to how each colour changes.
- Find shapes on your instrument: on guitar and ukulele the diagram shows fingers and open strings; on piano you see the keys to press.
- Check your own voicings: if you found a shape by ear, enter the root and type to confirm the notes.
- Read and write it: the staff view shows how the chord is notated, useful for arranging or for reading lead sheets.
Related pages
Learn the theory in the lessons on triads, seventh chords and chord inversions. Practise spelling chords on paper with the triads worksheet and the seventh chords worksheet. Print the chord formulas chart and blank chord boxes to write down your favourite voicings. If you have the notes but not the name, the chord identifier works the other way round.