Circle of Fifths — Keys, Chords & Key Signatures

The Circle of Fifths in The Ultimate Piano shows all 12 keys with their signatures, relative minors and diatonic chords. Select a key and its seven chords appear as coloured chips; one click plays the triad. A strength of this version is that it is not a static picture — the same wheel sets the key everywhere else in the app.

The circle of fifths arranges all 12 keys so each neighbor shares six of seven scale tones — the most practical map of Western tonal music.

On this page

Major Keys, Minor Keys & Key Signatures

The wheel is built in rings around a centre button, covering all 12 notes of the chromatic scale:

Each key keeps its own colour, and the diatonic chord chips below the wheel use the same colours.

Selecting a Key

1. Click any key on the wheel — it lights up, the function ring appears around it, and its name appears on the Select button (for example Select: G)
2. The diatonic chord bar below the wheel updates immediately
3. Click Select to confirm, or Cancel, the × or a click beside the window to close without applying

When the wheel opens from a place that already has a key — the header, a player, an exercise — that key is already marked; Select only becomes active once you pick a key yourself.

Enharmonic keys — keys with two valid spellings (F♯/G♭, D♭/C♯, B/C♭ in the major ring; A♯m/B♭m, D♯m/E♭m, G♯m/A♭m in the minor ring) show both names inside the segment. Click the name you want to select that spelling. The active spelling appears bold; the alternative fades out. The staff in the outer ring changes with it (e.g., 6 sharps vs. 6 flats).

Play preview: The ▶ button in the centre of the wheel plays the triad of the selected key with piano sound — major keys play a major triad (1–3–5), minor keys a minor triad (1–♭3–5).

Random key: Where the wheel is opened for exploring — from the Learn menu or the header — the 🎲 button in the centre spins to a random major or minor key, useful for rotating through all 12 keys in practice.

Keyboard shortcut: Ctrl+Shift+F opens and closes the Circle of Fifths. You can also drag the window by its title bar.

Diatonic Chords

When you click a key, the chord bar shows all 7 chords that belong to that key, written as chord names with the correct spelling for the key — G major gives G, Am, Bm, C, D, Em, F♯dim. Hover over a chip to see its Roman numeral; the function ring around the wheel shows the same numerals in place. Each chip uses the colour of its key on the wheel, lighter for minor chords.

Minor keys are interpreted as natural minor (Aeolian), marked "nat. minor" in the chord bar. For example, A natural minor: Am, Bdim, C, Dm, Em, F, G.

The diatonic chords of any key work naturally together — use them as a starting point for Chord Progressions.

Where the Circle of Fifths Appears

The wheel is integrated across the entire app:

Header — Global Key & Accidentals

The Key button in the app header (showing e.g. "Key: C") opens the Circle of Fifths to set the global key for the session — a major key from the middle ring or a minor key from the inner ring. This key determines which accidentals appear in the note names display and on the sheet music staff, and the chord degree shown next to chord names. Selecting a key here affects the whole app, not just one module.

Learn Menu — Free Exploration

The Circle of Fifths card in the Learn menu opens the wheel in pure exploration mode. No key is applied anywhere — it's a tool for studying how keys, key signatures, and diatonic chords relate to each other.

Practice Modules

Play & Create

Use Cases

• Understand key relationships — neighbors on the circle share the most notes
• Read key signatures — the outer ring shows the signature of every key as it appears in sheet music
• Set accidentals for note display — select the key in the header to control which sharps or flats appear
• Practice across all 12 keys — use the random spin for systematic rotation
• Build chord progressions — click a key, see its 7 chords immediately
• Navigate major/minor — every major key sits directly outside its relative minor

Frequently Asked Questions

What is the Circle of Fifths and why is it useful?

12 keys, arranged so that each neighbor is a perfect fifth apart and shares six of seven scale notes — that is the Circle of Fifths. It is the standard reference for understanding key relationships, choosing chords that work together, and navigating between keys in music.

How do I use the Circle of Fifths to find diatonic chords in a key?

7 chords appear in the chord bar the moment you click a key on the wheel. These are the scale's diatonic chords — for G major: G, Am, Bm, C, D, Em and F♯dim — and the function ring around the wheel labels them I through vii°. Any combination of these chords will sound harmonically coherent in that key.

What is the difference between major and minor keys on the Circle of Fifths?

12 major keys sit on the middle ring; their 12 relative minors share the same key signatures on the inner ring, directly inside them. C major and A minor both have no sharps or flats and occupy the same slice. Minor keys in this app use natural minor (Aeolian) as the reference scale.

What are key signatures and how does the Circle of Fifths display them?

0 to 7 sharps or flats define every key signature, and the Circle of Fifths shows each one on a small staff in its outer ring, written exactly as in sheet music. C major uses none; G major uses one sharp (F♯); F major uses one flat (B♭). Because the signature sits right next to the key, you can read it at a glance — and for keys with two spellings, the staff switches between sharps and flats with the spelling you choose.

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