How does a capo change the chord name?

A capo raises every string by the number of frets it clamps. So the chord shape you finger sounds higher than its open name by that many semitones. A G shape with a capo on fret 2 actually sounds as an A chord.

Does the capo change the chord quality?

No. Major stays major, minor stays minor, and any added tones such as 7 or sus4 carry over unchanged. A capo only shifts the root pitch up; it never alters the chord type, because the same fingering keeps the same interval structure.

How do I work backwards from a target chord?

Use reverse mode. Enter the concert chord you want and the capo fret, and the tool subtracts the capo's semitones to give the easy open shape you should finger above the capo. This is how players turn awkward keys into open-string shapes.

Why do capos make some keys easier?

Open chord shapes such as G, C, D, E, A, Em and Am use ringing open strings and simple fingerings. A capo lets you keep those friendly shapes while sounding in a harder key like Bb or F#, avoiding barre chords.

What is the highest useful capo position?

Most capos work up to about fret 7 before the strings get too short and the tone thins out. Past fret 7 the playable area shrinks and intonation suffers, so the tool covers frets 1 to 11 but flags that high positions are unusual.

What is the Capo Chord Transposer?

Converts the chord shapes you play with a capo into their true concert-pitch chord names, or works backwards to find the capo position and easy shape that produces a target chord. Built for acoustic guitarists. It runs free in your browser on Gera Tools, with nothing uploaded.

Capo Chord Transposer

Name: Capo Chord Transposer
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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A capo is a clamp that shortens every string by the same amount, raising the whole guitar in pitch. That means the easy open chord shapes you finger above the capo no longer sound by their open names. This tool translates between the shape you play and the chord that actually rings out.

How it works

A capo on fret n raises every note by n semitones. Because all six strings move together, the chord you finger keeps its exact interval structure: the relationships between the notes are unchanged, so a major shape stays major and a minor shape stays minor. Only the root pitch shifts.

The maths is therefore a simple twelve-note rotation. Each chord root maps to a number from 0 to 11 (C = 0, C# = 1, and so on). To find the real chord you add the capo fret and wrap around 12:

real root = (shape root + capo fret) mod 12

Reverse mode does the opposite. Given the chord you want to hear and the capo position, it subtracts the capo frets to find the shape you should finger:

shape root = (target root − capo fret + 12) mod 12

The chord quality (major, minor, 7, sus, dim, etc.) is simply carried across unchanged in both directions.

Worked example

Play a G shape with the capo on fret 2. G is pitch class 7, the capo adds 2, so the real chord is pitch class 9, which is A. Strum the familiar G, C and D shapes capo 2 and you are actually playing in the key of A — perfect for matching a singer without learning barre chords.

Tips and notes

Sharps and flats name the same pitch (A# and Bb are identical here); this tool displays the sharp spelling. Open-friendly shapes worth keeping under a capo are G, C, D, A, E, Em and Am. Above fret 7 the playable neck gets cramped and tone thins, so use the high positions sparingly. Everything is computed locally in your browser.