Chord Finder
Find the notes in any chord, see them on piano and guitar, or name a chord from the notes you play.
Build a chord
C
C major
- Notes
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- Intervals
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- Semitones from root
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- Inversions
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Your browser blocked or does not support Web Audio, so the chord cannot be played here. Everything else still works.
Piano keys
Guitar fretboard standard tuning E A D G B E, frets 0–12
Name a chord from its notes
Use letters A–G with #/b, for example E G C or F# A# C# E. The first note is treated as the bass, so inversions get a slash name.
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How it works
A chord is a root note plus a stack of intervals measured in semitones. This finder starts
from the root you pick and applies the chord formula: a major triad is
1 3 5 (0, 4 and 7 semitones), a minor triad flattens the third to
1 ♭3 5 (0, 3, 7), a dominant seventh adds a minor seventh
(1 3 5 ♭7, 0-4-7-10) and so on through 29 chord types.
Notes are spelled by scale degree rather than by pitch alone, so C diminished 7 comes out as
C E♭ G♭ B♭♭ and F♯7 as
F♯ A♯ C♯ E — the spellings you would actually write on a
stave, not "enharmonic equivalents".
The piano strip highlights the chord voiced from the root upwards, and the fretboard grid
marks every chord tone on the first twelve frets in standard tuning (E A D G B E) so you can
pick your own shape. The reverse lookup works on pitch-class sets: your notes are reduced to
the twelve pitch classes, compared against every root and chord type, and the first note you
type is treated as the bass, which is how E G C is reported as C major in first
inversion (C/E). Some sets are genuinely ambiguous — C E G A is both C6 and Am7/C — so the
alternatives are listed too. Note that in real playing an 11th chord usually drops the third
and a 13th usually drops the eleventh; the formulas here show the full theoretical stack.
Everything runs in your browser with plain JavaScript and the Web Audio API for the playback button. Nothing is uploaded, there is no sign-up and there are no ads.
Frequently asked questions
What notes are in a chord?
A chord is a root note plus a formula of intervals measured in semitones. A major triad is 1-3-5 (0, 4 and 7 semitones above the root), a minor triad is 1-♭3-5 (0, 3, 7) and a dominant seventh is 1-3-5-♭7 (0, 4, 7, 10). Pick a root and a chord type and the finder spells the notes, shows the intervals and highlights them on a piano keyboard and a guitar fretboard.
Can it tell me the name of a chord from the notes?
Yes. Type the notes into the reverse lookup, lowest note first, for example E G C, and it reduces them to pitch classes, compares them against every root and chord type, and reports C major in first inversion (C/E). Some note sets are genuinely ambiguous, so alternatives are listed too: C E G A is both C6 and Am7/C.
Why does it write B♭♭ instead of A?
Chord tones are spelled by scale degree, not by pitch alone. A diminished seventh stacks minor thirds on degrees 1, 3, 5 and 7, so C dim7 must be written C E♭ G♭ B♭♭, because the seventh has to be a B of some kind. It sounds the same as A but it is the spelling you would write on a stave, and the same rule gives F♯7 as F♯ A♯ C♯ E rather than F♯ B♭ D♭ E.