Song Key Transposer

How this tool works

Transposing means moving every note of a song up or down by the same distance. Western music divides the octave into 12 equal steps called semitones (one fret on a guitar, one key to the next on a piano, black keys included). If your new key is two semitones above the old one, every chord root moves up two semitones: C becomes D, A becomes B, F becomes G.

The tool reads each chord in two parts: the root (and the bass note after a slash, if there is one) and the suffix that describes its quality. Only the root and bass note move. The suffix — m, 7, maj7, sus4, add9, dim, m7b5, 13 and so on — stays exactly as you wrote it, because the shape of the chord does not change when you change key. So Bm7b5/A moved up a tone becomes C#m7b5/B, with the “m7b5” untouched.

Spelling matters too. The same pitch can be called C# or D♭, and a chart looks wrong if it mixes the two carelessly. In Auto mode the transposer spells notes to suit the new key: flat keys such as F, B♭, E♭, A♭ and D♭ major (and their relative minors) get flats, sharp keys such as G, D, A, E, B and F# major get sharps, and the neutral keys C major and A minor use the most common chart names (F#, B♭, E♭ and so on). You can force sharps or flats if your band prefers one.

Anything that is not a recognisable chord — lyrics, notes to yourself, typos — is left exactly where it was, and the tool lists those words so you can check nothing was missed.

How to use this tool

1. Paste or type your chord chart into the box. Keep chords separated by spaces, bar lines or commas. Multiple lines are fine.
2. Set the original key. If you are not sure, press Detect key to use the first chord as a starting guess, then check it by ear.
3. Choose the new key, or use the + 1 / − 1 semitone buttons to step through keys until one suits the singer.
4. Press Transpose chords. Read the result, the semitone shift and the capo suggestion, then copy the chart.
5. If the tool warns about unrecognised words, check whether they are chords written in an unusual way (for example a lower-case “am”) and correct them.

Tip: when finding a key for a vocalist, have them sing the highest and lowest phrases of the song. Nudge the key a semitone at a time until both feel comfortable, then transpose the whole chart once.

Example calculation

A song in C major uses the chords C – Am – F – G, but the singer finds the chorus too low. You try D major, which is two semitones higher.

A guitarist who likes the original shapes can simply put a capo on the 2nd fret and keep playing C, Am, F and G — it will sound in D. Going the other way, a gospel chart in B♭ major with B♭/D – E♭ – F – Gm moved to G major (down three semitones) becomes G/B – C – D – Em.

What does this result mean?

The transposed chart is ready to play: same rhythm, same chord types, new pitch. The semitone shift shows both directions (for example “+2 / −10”) because moving up two semitones lands on the same key as moving down ten — the difference is only the register. For singers, choose the direction that keeps the melody in their comfortable range.

The interval name (major second, perfect fourth, and so on) is the musical name for the distance, which is useful when talking to other musicians or reading a score.

The capo suggestion is for guitarists who would rather keep familiar open-chord shapes. A capo raises everything by one semitone per fret, so moving up three semitones means capo on fret 3 with the original shapes. Capos only raise pitch; to go down you either play the new shapes or move an existing capo lower. Our guide to how song keys work explains keys, relative minors and key signatures in more depth.

Choosing a key for a singer

The best key for a song is usually the one that places the highest note of the chorus near the top of the singer’s comfortable range without straining. A few practical points:

• Test the extremes. Sing the lowest verse line and the highest chorus note in the current key. If the low line mumbles, go up; if the high note strains, go down.
• Small moves matter. A single semitone can be the difference between a comfortable belt and a cracked note.
• Think about the band. Guitarists often prefer E, A, D, G and C; horn sections often prefer flat keys such as B♭, E♭ and F. A capo can bridge the gap for guitar.
• Duets and choirs need a compromise key; try the options aloud before rewriting parts.

Important limitations

• Chords need a capital root letter. “Am” is recognised; “am” is treated as a word and left unchanged. Unusual symbols your band invented may not be recognised either — the tool lists anything it skipped.
• Transposing cannot change major to minor. Moving a song from C major to A minor is a different arrangement, not a transposition. If you choose keys of different modes, the tool moves the tonic and warns you.
• Simplified spelling. To keep charts readable, the tool avoids theoretical spellings such as E#, B#, C♭ and double sharps, even in keys like F# major where a textbook might use them.
• Key detection is a guess. It uses your first chord only. Many songs start on a chord other than the home chord, so trust your ears over the detector.
• Words that look like chords (a lyric line that begins with the word “A”, for example) will be transposed. Keep lyrics on separate lines from chords, or check the result.
• This tool changes written chords only; it does not pitch-shift audio.

Frequently asked questions