A chord is a set of notes sounding together, usually stacked in thirds. C major is C, E and G: a root, a major third above it, and a perfect fifth. To name a chord, a chord identifier reduces your notes to pitch classes, ignoring octaves and doubled notes, then looks for the root that explains them most simply.
The quality comes from the intervals above that root. A major third and a perfect fifth make a major triad; a minor third makes it minor; add a seventh and you get a major, dominant or minor seventh chord. Ninths, elevenths and thirteenths stack more thirds on top, and sus chords replace the third with a second or a fourth.
Often more than one name fits. A, C, E and G spell Am7, but with C in the bass they read as C6. Neither is wrong: the bass note and the key decide which name a musician would write. That’s why the result lists the alternatives instead of picking one and hiding the rest.
Inversions and slash chords
A chord is in root position when its root is the lowest note. Put the third in the bass and it’s in first inversion; put the fifth there and it’s in second inversion. Lead sheets write these as slash chords: C/E is C major with E in the bass, and C/G is C major over G.
Inversions keep the harmony but change how it moves. Pianists use them so the right hand barely shifts between chords, and bass lines walk through them: C, C/B, Am, Am/G is a classic descending line. When you pick notes, choose the lowest one deliberately, since it decides the inversion and sometimes the name.
Guitar chord finder or piano chord finder: same theory, different hands
On a piano, every note has one key, so a chord’s notes are easy to see. On a guitar, the same chord has many shapes across the neck, and a shape you find by ear may skip the root, double the fifth or put an unusual note in the bass. The fretboard view turns each fretted string into a pitch, then names the set like any other chord.
That’s also why one guitar shape can carry two names: without the root in the bass, it may read as an inversion of one chord or as root position of another. Check the alternatives, play the chord back, and pick the name that fits the song. If you want the whole riff written out, not just the chord, Guitar Tab Generator turns a recording into tab.
Chord finder from audio: reading the timeline
For a whole song, the Audio tab works differently. It computes a chromagram, a running measurement of energy in each of the 12 pitch classes, compares each slice of the song with chord templates, and smooths the result so it doesn’t flicker on every passing note. Exact mode transcribes the notes first and names the chords from them, which is slower but can separate harmony from melody more cleanly.
The timeline colors chords by function. Tonic chords (I, vi) feel like home, subdominant chords (IV, ii) move away, and dominant chords (V, vii°) build tension that wants to resolve. In C major, the common I–V–vi–IV progression, C–G–Am–F, reads as home, tension, home, away. The song’s key sits alongside; Key Finder adds its Camelot code and scale.
Learn a song by that shape and you can play it in any key, or move a score into a new one with Transpose Sheet Music. Audio detection hears the whole mix, though, so a loud vocal, a walking bass or a distorted guitar can pull the result toward a different chord. Treat the timeline as a map and check close calls by ear. When you want the melody and voicings written out, not just the chord names, Audio to Sheet Music takes the next step.