Music theory, instantly explained
Chord Analysis Calculator
Enter notes or tap the piano to identify the chord, inversion, intervals and key context.
1
Enter notes
Use spaces or commas. The first note is treated as the bass.
Examples: C E G · E G C · C G B♭ · F♯ A C♯ E
Piano input
Why this chord?
Intervals
Key context
Select a key
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Roman numeral & function
Other interpretations
Strong alternate matchesAnalyze the notes you actually play
The calculator compares your notes with common chord structures, tests possible roots, accounts for bass-note inversions and shows alternate interpretations when the same pitch collection has more than one useful name.
From chord name to usable theory
Results include interval roles, chord formula, root, bass and inversion. Add an optional key to see a diatonic Roman numeral and a broad harmonic function for songwriting, arranging and theory study.
Works directly in the browser
The calculator is a static web app built with HTML, CSS and JavaScript. It can be installed as a PWA and keeps the application shell available from cache when the network is unavailable.