Music Theory Tools
Learn Music Theory
Learn Music Theory
Interactively
Three tools to help you understand keys, chords, and progressions — whether you're just starting out or sharpening your theory.
Tool 01
Circle of Fifths
Click any key on the circle to explore its sharps or flats, relative minor, and the chords that live inside it.
What is the Circle of Fifths? It's a visual map of all 12 major (and minor) keys arranged so each neighboring key shares 6 of its 7 notes. Moving clockwise adds one sharp; moving counter-clockwise adds one flat. It's one of the most powerful tools in music theory — composers and producers use it to find chord relationships instantly.
C
Major
Key Details
Sharps / Flats
No sharps or flats
Relative Minor
A minor
Scale Notes
C D E F G A B
Chords in this Key
← Click any section of the circle
Tool 02
Key Signature Reference
Select a key to see its sharps or flats on a staff, its relative key, and all seven diatonic chords with Roman numeral analysis.
Key signatures tell musicians which notes are sharp or flat throughout a piece — instead of marking each note individually. Treble clef is used for higher-pitched instruments (guitar, piano right hand, violin). Bass clef is for lower-pitched instruments (bass guitar, piano left hand, cello). The sharps/flats always appear in a specific order on the staff.
Select Key
Sharps / Flats
0
No accidentals
Relative Minor
A
Same key signature
Scale Notes
C D E F G A B
Staff Notation
Treble Clef
Bass Clef
Diatonic Chords — 7 Chords Built From This Key
Roman numerals show each chord's function in the key. Uppercase = major chord, lowercase = minor chord, ° = diminished. The I chord is "home base" — it sounds resolved. The V chord creates tension that wants to resolve back to I. The vi chord is the relative minor — same notes as the key but with a darker feel.
Tool 03
Chord Progression Builder
Load a preset progression or build your own by clicking chords. Hit play to hear it through your browser.
Chord progressions are sequences of chords that form the backbone of most songs. The I–IV–V–I is the foundation of blues and classic rock. I–V–vi–IV (the "four-chord song") is behind hundreds of pop hits. ii–V–I is the cornerstone of jazz. Knowing these by name lets you transpose them to any key instantly.
Key
BPM
Preset Progressions — Click to Load
Chord Palette — Click to Add to Progression
●White = major
●Purple = minor
●Amber = dominant (V)
●Gray = diminished
Your Progression
Use presets above or click chords from the palette to build your progression.