OneTaskBy Tim King · Updated
Chord Finder
Name a Chord From Its Notes, With Inversions
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How the Chord Finder works
This chord finder names a chord from the notes you type, lowest note first. It gives the chord name, type and formula, the inversion when the bass note is not the root, and other names that the same set of notes can take.
How the chord finder works
Each note becomes a pitch class from 0 to 11. The chord finder tries every note as the root, measures the other notes in semitones above it and compares the set with 28 chord formulas, from triads to 13th chords. The formula is written in scale degrees, so a dominant 7th is 1 – 3 – 5 – b7. A match with the bass note as root is named first; other matches are slash chords.
First example. C E G Bb has the root C, a major 3rd, a perfect 5th and a minor 7th, so it is C7, a dominant 7th in root position.
Second example. E G C is a C major triad with E in the bass, written C/E, the first inversion. A C E G is Am7, but the same notes also make C6/A, which is why the finder lists other readings.
How many notes make a chord? Three or more different notes usually, though a power chord such as C5 has only two. Doubled notes in other octaves count once, so C E G C is still C major.
The finder needs the full chord. A 9th chord played without its 5th will not match, so add the missing note or name the chord from the notes you have.
Common chord types with their symbol, formula, semitones above the root and spelling in C
| Chord type | Symbol in C | Formula | Semitones | Notes in C |
|---|---|---|---|---|
| Major | C | 1 3 5 | 0-4-7 | C E G |
| Minor | Cm | 1 b3 5 | 0-3-7 | C Eb G |
| Diminished | Cdim | 1 b3 b5 | 0-3-6 | C Eb Gb |
| Augmented | Caug | 1 3 #5 | 0-4-8 | C E G# |
| Suspended 2nd | Csus2 | 1 2 5 | 0-2-7 | C D G |
| Suspended 4th | Csus4 | 1 4 5 | 0-5-7 | C F G |
| Power chord | C5 | 1 5 | 0-7 | C G |
| Major 6th | C6 | 1 3 5 6 | 0-4-7-9 | C E G A |
| Minor 6th | Cm6 | 1 b3 5 6 | 0-3-7-9 | C Eb G A |
| Dominant 7th | C7 | 1 3 5 b7 | 0-4-7-10 | C E G Bb |
| Major 7th | Cmaj7 | 1 3 5 7 | 0-4-7-11 | C E G B |
| Minor 7th | Cm7 | 1 b3 5 b7 | 0-3-7-10 | C Eb G Bb |
| Minor major 7th | Cm(maj7) | 1 b3 5 7 | 0-3-7-11 | C Eb G B |
| Diminished 7th | Cdim7 | 1 b3 b5 bb7 | 0-3-6-9 | C Eb Gb Bbb |
| Half-diminished | Cm7b5 | 1 b3 b5 b7 | 0-3-6-10 | C Eb Gb Bb |
| 7th suspended 4th | C7sus4 | 1 4 5 b7 | 0-5-7-10 | C F G Bb |
| Augmented 7th | C7#5 | 1 3 #5 b7 | 0-4-8-10 | C E G# Bb |
| Add 9 | Cadd9 | 1 3 5 9 | 0-4-7-2 | C E G D |
| Minor add 9 | Cm(add9) | 1 b3 5 9 | 0-3-7-2 | C Eb G D |
| 6/9 | C6/9 | 1 3 5 6 9 | 0-4-7-9-2 | C E G A D |
| Dominant 9th | C9 | 1 3 5 b7 9 | 0-4-7-10-2 | C E G Bb D |
| Major 9th | Cmaj9 | 1 3 5 7 9 | 0-4-7-11-2 | C E G B D |
| Minor 9th | Cm9 | 1 b3 5 b7 9 | 0-3-7-10-2 | C Eb G Bb D |
| 7 flat 9 | C7b9 | 1 3 5 b7 b9 | 0-4-7-10-1 | C E G Bb Db |
| 7 sharp 9 | C7#9 | 1 3 5 b7 #9 | 0-4-7-10-3 | C E G Bb D# |
| Dominant 11th | C11 | 1 5 b7 9 11 | 0-7-10-2-5 | C G Bb D F |
| Minor 11th | Cm11 | 1 b3 5 b7 9 11 | 0-3-7-10-2-5 | C Eb G Bb D F |
| Dominant 13th | C13 | 1 3 5 b7 9 13 | 0-4-7-10-2-9 | C E G Bb D A |
FAQ
How do I find the name of a chord?
List its notes from the lowest up and look for the stack of thirds. The note at the bottom of that stack is the root, and the intervals above it decide the type, such as major, minor or dominant 7th.
What does a slash chord like C/E mean?
The chord before the slash is played over the bass note after it. C/E is a C major chord with E as the lowest note, which is its first inversion. Slash chords can also have a bass note outside the chord.
Why can the same notes have two chord names?
Some chords share all their notes. A C E G is both Am7 and C6, and C Eb Gb A is a diminished 7th named from any of its four notes. The bass note and the key decide which name fits best.
How do I type sharps and flats?
Use # for sharp and b for flat after the letter, such as F# or Bb. Double sharps and flats such as F## and Bbb also work. Separate notes with spaces, commas or dashes.
What does the formula 1 3 5 b7 mean?
The numbers are scale degrees of the major scale built on the root. 1 is the root, 3 the major third, 5 the fifth and b7 the seventh lowered by one semitone, which together make a dominant 7th.
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