Free Online Chord Identifier
Identify a chord from the notes you select.
Note chips
Piano keys (C3 to B4)
Click a key to add or remove that exact note. Click a note chip to toggle the pitch class in the fourth octave. The lowest selected note determines the inversion.
Selected notes
Intervals from root
Other interpretations
About the Chord Identifier
A chord is a set of notes heard together, and its name describes both the root and the intervals stacked above it. This identifier compares the notes you select against common chord formulas and reports the best match, the intervals relative to the root, and the inversion implied by the lowest note. You can build chords on a small piano keyboard, use the note chips, or combine both. The tool is intended for recognition and exploration rather than as a substitute for a complete music-theory reference, because context and voicing can change how a chord is interpreted.
How the matching works
Every selected note is reduced to a pitch class, the note name without its octave. For each possible root, the tool calculates the intervals above that root and compares the set with a library of chord formulas. A major triad is 0, 4, 7; a minor triad is 0, 3, 7; a dominant seventh is 0, 4, 7, 10; and a minor seventh flat five is 0, 3, 6, 10. When several interpretations fit, the tool prefers the one whose root matches the lowest note, then lists the alternatives. This is why C6 and Am7 can describe the same four notes.
Supported chord types
- Major, minor, diminished, and augmented triads.
- Suspended second and suspended fourth chords.
- Sixth chords, dominant sevenths, major sevenths, and minor sevenths.
- Half-diminished and fully diminished sevenths.
- Add9, dominant ninth, major ninth, and minor add9 colours.
- Power chords and dominant seventh suspended fourth chords.
Inversions and voicing
An inversion is determined by which chord tone is in the bass. Root position places the root at the bottom; first inversion places the third at the bottom; second inversion places the fifth at the bottom; and third inversion places the seventh at the bottom. A slash chord explicitly names a bass note that may or may not be part of the chord. The calculator reports the inversion suggested by the lowest selected key, which is why the octave and voicing of your selection matter. On a real instrument, doubling, open voicings, and omitted fifths are common and can make identification ambiguous.
Limitations
The tool works with pitch classes, so it cannot distinguish enharmonic spellings such as G♯ and A♭. It also does not consider musical context, bass motion, or the scale of the passage. Extended chords with omitted notes, altered dominants, and quartal voicings may not match any template. If no standard chord is found, read the intervals listed from the lowest note and use them as a starting point for analysis. Jazz harmony in particular often uses voicings that are better described by their function than by a simple chord symbol.
Frequently asked questions
Why does the same set of notes have two names?
Chords are defined by intervals, and different roots can produce the same pitch-class set. C6 and Am7 both contain C, E, G, and A. The bass note and the musical context usually decide which name is more appropriate.
Does the octave of the notes matter?
The chord name depends mostly on pitch classes, but the octave determines the bass and therefore the inversion. Spread voicings can also change the perceived colour even when the chord symbol stays the same.
Can I identify a chord from a recording?
Not directly. You would need to transcribe the notes first, then enter them here. For dense mixes, use your ear, a transcription tool, or isolate the harmonic instrument before selecting the pitches.