Analysis & Transposing
Chord Progression Analyzer
Enter a chord progression to analyze its key and T/SD/D functions. Free browser tool — understand chord theory visually.
Enter chord names separated by spaces (e.g. C Am F G7)
What is this tool?
A chord-progression analyzer that detects the likely key and color-codes every chord by its harmonic role — Tonic (T), Subdominant (SD), or Dominant (D).
When it helps
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Decode a song you love
Paste in the progression and see the flow of stability, motion, and resolution that makes it feel the way it does.
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Audit your own progression
See the T/SD/D sequence at a glance — it's an easy way to check whether a progression has shape or feels static.
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Spot borrowed and non-diatonic chords
Chords outside the detected key are greyed out, making modulations and borrowed chords easy to find.
How to use
- 1 Type your chord progression separated by spaces (e.g. C Am F G, or Am7 Fmaj7 C G7).
- 2 Press 'Analyze' or hit Enter — you'll see the estimated key plus roman numerals and function colors for each chord.
- 3 When multiple keys match, use 'Candidates (N)' in the top bar to switch views and compare.
- 4 Grey cards are chords outside the detected key (likely borrowed chords). They're also summarized below.
- 5 Press '▶ Play all' in the bottom dock to hear the progression you just analyzed.