chord identifier: name a chord from its notes
type the notes of a chord, lowest first, and the chord identifier names it: C E G B♭ is C7, and E G C is C/E, a C major chord in first inversion. it reads sharps and flats, recognises triads, seventh chords, sixths, suspended chords and ninths, and tells you what each note is doing in the chord, so you can write the right chord symbol into a score. it runs in your browser, and nothing you type is sent anywhere.
- type the lowest note first: it decides the inversion.
- add octave numbers, such as C4 for middle C, to type a voicing exactly.
- below the tool: how to name a chord by hand, and a table of chord formulas.
identify a chord
how to use the chord identifier
- type the note names, separated by spaces or commas: C E G, or F# A C# E.
- type the lowest note first. that note decides the inversion and the slash in the symbol, so E G C reads as C/E.
- to type a voicing exactly as written, add octave numbers: C3 G3 E4 B4. with octaves, the lowest pitch is the bass whatever order you type.
- read the chord symbol, then the list of what each note is. if the same notes can be named another way, the other names appear under it.
how to identify a chord by hand
a chord in its simplest form is a stack of thirds, so the trick is to rearrange its notes until every note is a third above the one below it. the bottom note of that stack is the root, and the intervals above it give the chord's type.
- collect the letter names and drop any repeats. E G C E becomes E, G, C.
- stack them in thirds. try each note as the bottom until the letters skip one each time: C, E, G. C is the root.
- measure the intervals from the root. C up to E is a major 3rd, and C up to G is a perfect 5th, which makes a major triad.
- check the bass. the lowest note in the original was E, the third, so the chord is C/E, first inversion.
chord formulas
the semitone counts are measured up from the root. the right-hand column spells each chord on C.
| chord type | symbol on C | semitones above the root | notes on C |
|---|---|---|---|
| major triad | C | 0, 4, 7 | C E G |
| minor triad | Cm | 0, 3, 7 | C E♭ G |
| diminished triad | C° | 0, 3, 6 | C E♭ G♭ |
| augmented triad | C+ | 0, 4, 8 | C E G♯ |
| suspended 4th | Csus4 | 0, 5, 7 | C F G |
| suspended 2nd | Csus2 | 0, 2, 7 | C D G |
| dominant seventh | C7 | 0, 4, 7, 10 | C E G B♭ |
| major seventh | Cmaj7 | 0, 4, 7, 11 | C E G B |
| minor seventh | Cm7 | 0, 3, 7, 10 | C E♭ G B♭ |
| half-diminished seventh | Cm7♭5 | 0, 3, 6, 10 | C E♭ G♭ B♭ |
| diminished seventh | C°7 | 0, 3, 6, 9 | C E♭ G♭ B double-flat (sounds as A) |
| major sixth | C6 | 0, 4, 7, 9 | C E G A |
| dominant ninth | C9 | 0, 4, 7, 10, 14 | C E G B♭ D |
when the same notes have two names
some note sets really are two chords. C E G A is C6, but with A in the bass it is Am7: the same four notes, heard from a different root. the identifier treats the lowest note as the deciding vote, which matches how most musicians hear it. diminished seventh and augmented chords are symmetrical, so any of their notes can be called the root, and the right name depends on the key around them.
common questions about naming chords
how do I know what chord I am playing?
write down the notes from the lowest up and type them into the identifier, or stack the notes in thirds by hand as shown above. the bottom of the stack is the root and the intervals above it give the type: a major 3rd and perfect 5th make a major chord.
what does a slash chord like C/E mean?
the letter before the slash is the chord and the letter after it is the bass note. C/E is a C major chord with E as its lowest note, which is C major in first inversion. slash chords also cover bass notes outside the chord, such as D/C.
can a chord have no root in it?
yes. jazz pianists often play rootless voicings, leaving the root to the bass player. an identifier that only sees the piano's notes will name those as a different chord, so add the bass note first to get the name the band means. see how to voice chords.
does the spelling of the notes matter?
not for the name the identifier gives, because it compares the sounds. it matters on the page, though: a C minor chord is spelled C E♭ G, never C D♯ G, because each chord tone uses its own letter name.
writing the chords into a score? notei is a music notation editor in the browser with chord symbols above the staff, playback with sampled instruments and an assistant that answers theory questions about the score you have open.
write it in noteisources
- Open Music Theory: triads
- Open Music Theory: seventh chords
- Open Music Theory: chord symbols
- Wikipedia: chord names and symbols (popular music)
this tool is part of the how to write sheet music guide series, and notei, our product, publishes it.