Song Key Transposer

Changing a song’s key to suit a singer or instrument means moving every chord by the same amount. This tool transposes a whole chord chart up or down any number of semitones, keeping chord qualities and bass notes intact, and shows the resulting key signature.

How it works

The twelve pitches form a chromatic circle. Transposing means stepping every chord root the same number of places around that circle:

C  C# D  D# E  F  F# G  G# A  A# B  (then wraps back to C)

Each chord is split into its root note and its quality suffix. Only the root is shifted; the suffix (m, 7, maj7, sus4, dim, and so on) is preserved. A shift of +2 semitones turns:

• C into D
• Am7 into Bm7
• F into G
• G/B into A/C#

Slash chords have their bass note transposed by the same amount, so inversions survive the change.

Worked example

Take the progression C Am F G and transpose up +2 semitones:

• C plus 2 = D
• Am plus 2 = Bm
• F plus 2 = G
• G plus 2 = A

Result: D Bm G A — the same I–vi–IV–V feel, now in D.

Sharps or flats — choosing the right spelling

When a transposition lands on an accidental (a black key note), it can be named two ways: C# or D♭, F# or G♭, and so on. Both are correct; the choice is about readability and convention for the key you land in.

Use sharps when the target key has sharps in its key signature — the keys of G, D, A, E, B, and F# major and their relative minors. A chord chart in D major reads as F#m, not G♭m, even though they are the same pitches.

Use flats when the target key has flats — F, B♭, E♭, A♭, D♭, and G♭ major and their relative minors. A chart in B♭ reads as E♭, not D#.

The tool offers a preference switch so you can match whichever convention your chart uses.

Capo use: sounding key vs fingering key

Guitarists frequently use a capo as a shortcut: instead of learning chord shapes in an awkward key, they place the capo on a fret and play familiar shapes that sound in the target key. This transposer handles both directions:

• Find the sounding key from capo position: If you play open-G shapes with a capo on fret 2, the chords sound up 2 semitones — so your G shape sounds as A, your D shape sounds as E, and your Em shape sounds as F#m. Enter the open-G shapes and shift +2 to see what the audience hears.
• Find the capo position for a given key: If a song is written in E♭ and you want to use simpler shapes, you might capo fret 3 and play in C. Enter the E♭ chords and shift -3 to find the C fingerings.

Common transposition scenarios

Singer’s range: A song written in C is too high for a particular vocalist who needs it in A. Transpose down by 3 semitones (C to A is three steps down the chromatic scale going counter-clockwise: C → B → B♭ → A). Enter the original C chords and set -3.

Instrument transposition: B♭ instruments (trumpet, clarinet) sound a tone lower than written. If a guitarist wants to jam along with a trumpet reading a written score, the guitarist transposes up +2 semitones (or the trumpet chart down -2) to match concert pitch.

Modulation within a song: Some songs shift up a semitone or two for the final chorus. You can transpose the chord section for that chorus separately to see the new chord names without re-writing the whole chart.

Tips and notes

• A guitar capo on fret n raises everything by n semitones, so set the shift to +n to see the chords the capo produces.
• Choose the sharp or flat spelling that matches your target key — sharps for keys like D, A, and E; flats for F, B flat, and E flat.
• Shifts wrap around the octave, so +12 returns the original chords (one octave higher). +13 is the same as +1.
• Negative values lower the key for a singer with a lower range.
• Everything runs locally in your browser; your chord chart is never uploaded.