Transposition Calculator
How to use
- In Chord progression mode, paste any progression in the left box (e.g.
C G Am F). The transposed version updates as you change the target key or move the slider. - Use the capo helper if you're a guitarist — it shows the equivalent capo position to play your original chord shapes in the new key.
- In Single note / interval mode, pick a starting note and shift it. Use the instrument presets if you play a transposing instrument (B♭ trumpet, E♭ alto sax, etc.).
- Hit Play original and Play transposed to A/B the two versions.
Why transpose music?
Most songs sound the same in any key; what changes is how they sit on a particular instrument or in a singer's voice. The most common reason musicians transpose is to match a singer's range — the recording is in C major, but the singer wants to sing it in A. Transposing down three semitones moves every chord and note to fit. Same melody, same chord shapes (relative to each other), different absolute pitches.
Guitarists often use a capo instead of relearning the chord shapes — clamping a capo on the third fret turns your G major shape into a B♭ major chord without changing what your fingers do. The capo helper above shows the right fret for any transposition. Pianists and other instrumentalists usually just play the new chords directly.
Transposing instruments — B♭ trumpet, E♭ alto sax, F French horn — read music in their own key but sound in concert pitch. The "Single note / interval" mode handles this: pick the right preset, type the note you see on the page, and the tool shows what it actually sounds like (or vice versa).
FAQs
What's the difference between transposing and modulating?
Transposing means moving an entire piece of music to a new key — every note shifts by the same amount, the relationships between notes stay the same. Modulating means changing key within a piece, often to create emotional contrast or set up a new section. Transposition is mechanical; modulation is compositional.
How do I find the best key for a singer?
Find the highest and lowest notes in the song's melody. Ask the singer to find the same range comfortably — they'll likely know their highest comfortable note. Calculate the difference between the recorded melody's highest note and the singer's comfortable top note in semitones, and transpose by that amount.
What does "capo 3" mean?
A capo is a clamp that shortens all six guitar strings to a higher fret, raising every open string's pitch. Capo 3 means clamp at the third fret, which raises every chord shape three semitones. So if you play your usual G chord with a capo at fret 3, it actually sounds like a B♭ chord.
Why does my trumpet say B♭?
Trumpets, clarinets, and tenor saxes are "B♭ instruments" — when they play their written C, the note that comes out of the bell is actually B♭ (one whole step down). To play music in concert C major, a B♭ trumpet player reads it written in D major.
Why do sharps and flats change with the key?
Each key has its own preferred spelling. F♯ major spells the third note as A♯ (not B♭) because the key signature uses sharps. G♭ major would spell the same physical pitch as B♭. The "Auto" spelling option picks the natural choice for the target key; Sharps and Flats override it.