How does the tool identify a chord?

It reduces your notes to their pitch classes (ignoring octave), then tries each note as a possible root and compares the resulting interval set against a library of chord shapes — triads, sixths, sevenths and common extensions. The first exact match gives the root and quality.

How are inversions and slash chords detected?

Once the root is found, the tool checks whether the lowest note you entered equals that root. If the bass differs, the chord is an inversion and is written as a slash chord, such as C/E for a C major triad with E in the bass.

What note formats are accepted?

Enter letter names A to G with optional sharps (#) or flats (b), separated by spaces or commas. Octave numbers are ignored, so C, C3 and C5 are treated the same. Enharmonic spellings like C# and Db are both understood.

Why does it say no chord matched?

The note set may not correspond to a standard chord in the library, or it may contain only one unique pitch class. The interval list from the bass is still shown so you can inspect the relationships, even when no named chord fits — useful for clusters and non-tertian voicings.

What do the interval names mean?

Each interval is the distance in semitones from the bass note, named by its musical quality: 4 semitones is a major 3rd, 7 a perfect 5th, 10 a minor 7th, and so on. These show how the voicing is built and help you spot the chord's character at a glance.

Chord Interval Finder

Play a handful of notes and want to know what chord they form? This finder takes a set of notes, identifies the chord name, root and quality, flags any inversion as a slash chord, and lists every interval measured from the bass — so you understand both the label and the structure.

How it works

The tool first converts your notes into pitch classes (0 to 11, where C is 0), removing duplicate octaves. To name the chord it treats each note in turn as a candidate root and measures the intervals of the other notes relative to it:

relative interval = (note pitch class − root pitch class + 12) mod 12

The resulting sorted interval set is compared against a library of chord templates — major and minor triads, diminished, augmented, sus2/sus4, sixths, and the seventh-chord family (maj7, 7, m7, m7b5, dim7 and more). When an exact match is found, that note is the root and the template gives the quality.

If the lowest note you entered is not the root, the chord is an inversion, written as a slash chord like G/B. The interval list is always measured from the bass note so you can see exactly how the voicing is stacked.

Tips and example

Enter C E G and the finder returns C major (a major triad, root position) with intervals of a major 3rd and a perfect 5th from the bass. Enter E G C instead and it reports C/E — a C major triad in first inversion — because the recognised root C is no longer in the bass.

Put the actual bass note first to get correct inversion labelling.
Sharps use # and flats use b; octave numbers are ignored.
When no named chord matches, the interval table still reveals the voicing’s structure.

All analysis runs locally in your browser.