A brass-and-ink orrery of Western harmony.
Hover the wheel and it sounds. Circle it slowly and you will feel why the circle of fifths is a circle — before reading a single word.
An interactive circle of fifths that you play by ear. Hover a key to hear its chord and see its key signature drawn in; the wheel lights up the chords that belong together. It's built for anyone learning how keys, chords, and modes relate — songwriters, students, and the curious.
An interactive music-theory instrument from Chris Pirillo's Arcade. Everything is procedural — the star chart, the felt-piano voice, the reverb — generated in a single file, with no samples and no network. Built on open-source code from the FABLE Showcase.
It arranges the twelve keys so that neighbours share almost all of their notes. That makes it a fast way to find the chords that belong to a key, pick keys that sound good together, plan a key change, and read how many sharps or flats a key has. In Harmonia you hover a key to hear it and see its key signature drawn in.
Hover or tap any key on the wheel. Harmonia lights up the diatonic chords for that key and plays the chord you're pointing at with real four-part voice leading. Click a key to hear a cadence, and press keys 1 through 7 to play each diatonic chord in the current key.
Most online circle of fifths tools play block chords. Harmonia plays real four-part voice leading, so progressions actually sound like music. It also covers all seven modes, visualizes the moving voices, and lets you seal chords onto a ribbon to build, reorder, and play back a full progression with adjustable tempo, swing, and looping. It's free, runs entirely in your browser, and shows no ads.
The most common ones use chords that sit close together on the circle. I–IV–V–I is the foundation of Western music, I–V–vi–IV is the pop progression heard in thousands of hits, ii–V–I is the cornerstone of jazz, and I–vi–ii–V is the 50s doo-wop progression. Because neighbouring keys share most of their notes, adjacent chords naturally sound good together.
Every major key shares its key signature with a minor key called its relative minor, found three steps counter-clockwise on the circle — or on Harmonia's inner silver ring. C major and A minor use the same notes, for example. Harmonia shows both rings at once so you can see and hear the relationship.
Yes. Harmonia is completely free, works on phones, tablets, and desktops, needs no account, and runs entirely in your browser. Nothing is uploaded and there are no ads.