Music Transposition Calculator
Choose a mode: transpose a single note by any interval, convert all diatonic chords when changing keys, or find written vs concert pitch for transposing instruments like Bb trumpet or Eb alto saxophone. Results update as you type.
What is music transposition?
Transposition is the process of moving a note, chord, or entire piece of music up or down by a fixed interval - a set number of semitones. Every relationship between the notes stays exactly the same, so a melody still sounds like itself and a chord still has the same quality; it just sits at a higher or lower pitch. Transposition is used to match a vocalist's comfortable range, to move a song to a key with easier guitar fingerings, to write parts for transposing instruments, or to create interesting arrangements that explore a different tonal colour.
How to transpose by interval
Count up or down the chromatic scale by the number of semitones in the chosen interval. A semitone is the smallest step in Western music, the distance from one piano key to the very next one (black or white). A major 2nd is 2 semitones, a perfect 4th is 5, a perfect 5th is 7, and an octave is 12. When you reach the end of the 12-note cycle you loop back to the start, which is why transposing any note up 12 semitones gives you the same note name one octave higher. Some resulting pitches can be spelled two ways - for example, the note 6 semitones above C can be written as F# or Gb - choose the spelling that fits the key you are working in.
Transposing a whole key and its chord chart
When you move a song to a new key, every chord root shifts by the same interval. The quality of each chord - major, minor, or diminished - does not change, because the scale relationships are preserved. If the original key of C major has the chords C, Dm, Em, F, G, Am, and Bdim, then moving up a perfect 5th to G major gives you G, Am, Bm, C, D, Em, and F#dim. A songwriter or arranger working with a vocalist might move down 1 to 3 semitones to lower the highest note in a song into a more comfortable range. Guitar players often use a capo to play open-chord shapes while sounding in a higher key.
Transposing instruments explained
A transposing instrument is one where the written note differs from the concert (sounding) pitch. The most common group is Bb instruments: Bb trumpet, Bb clarinet, and Bb tenor saxophone all produce a concert Bb when the player reads and fingers a C. To write a part for a Bb instrument that sounds at concert C, you write a D in the part. Eb instruments such as the alto and baritone saxophone work similarly but with a larger shift. The F French horn is written a perfect 5th above concert pitch, so concert C is written G. Part of orchestration and arranging is knowing these transpositions and applying them correctly so every instrument sounds at the intended concert pitch when they all play together.
Common transposing instruments
| Instrument | Transposition | Semitones | Concert C sounds as |
|---|---|---|---|
| Bb Trumpet / Cornet | Major 2nd up | 2 | Bb |
| Bb Clarinet | Major 2nd up | 2 | Bb |
| Bb Soprano Saxophone | Major 2nd up | 2 | Bb |
| Bb Tenor Saxophone | Major 9th up | 14 | Bb (octave lower) |
| A Clarinet | Minor 3rd up | 3 | A |
| Eb Alto Saxophone | Major 6th up | 9 | Eb |
| Eb Baritone Saxophone | Major 13th up | 21 | Eb (octave lower) |
| F French Horn | Perfect 5th up | 7 | F |
| Piccolo | Octave up | 12 | C (octave higher) |
| String Bass / Bass Guitar | Octave down | -12 | C (octave lower) |
Written pitch is higher than concert pitch by the amount shown. To convert concert to written, add the semitones.
Frequently asked questions
How many semitones is a perfect fifth?
A perfect fifth spans 7 semitones. It is one of the most common transpositions in music: moving from C up a perfect fifth gives G, from G gives D, and so on around the circle of fifths. A perfect fifth down (or a perfect fourth up) spans 5 semitones.
What is an enharmonic equivalent?
An enharmonic equivalent is the same pitch spelled with a different note name and accidental. For example, F# and Gb are enharmonic - they are the same key on the piano but are written differently depending on the musical context. In a key that uses sharps (like G major) you would spell the note as F#; in a key that uses flats (like Db major) you would write it as Gb.
Why do transposing instruments exist?
Transposing instruments were designed so that a player who moves between different sizes of the same instrument family can use the same fingerings. A clarinet player who switches between a Bb and an A clarinet reads the same written notes but the instrument produces a different concert pitch. Historically this made it easier to play in tune in certain keys before valves and improved manufacturing made it less necessary, but the convention persists in orchestral and band writing.
How do I use a capo for transposition?
Placing a capo at fret N on a guitar raises every open string by N semitones. If you know a song in G but need it in A, you place the capo at fret 2 and play G shapes - the guitar sounds in A. Capo position equals the number of semitones you want to transpose upward. Our Key mode shows the semitone difference between your original and target key, which is the capo fret you need.
How do I transpose for Bb trumpet from a concert-pitch score?
A Bb trumpet sounds a major 2nd (2 semitones) lower than written. To write a trumpet part from a concert score, shift every note up 2 semitones - a written C on the trumpet part will sound as Bb concert. Use this calculator's Instrument mode: enter the concert pitch note and select Bb Trumpet, and it shows you the written note to put in the part.
Can I transpose minor keys the same way as major keys?
Yes. The interval shift is identical. The diatonic chords in a minor key follow a different pattern (i, ii dim, III, iv, v or V, VI, VII) but each root still moves up or down by the same number of semitones as in a major transposition. The quality of each chord - major, minor, diminished - is preserved just as it is in major keys.
What is the difference between concert pitch and written pitch?
Concert pitch is the actual sound produced - what you hear and what is shown in a C-pitched conductor's score. Written pitch is what appears in the individual instrument's part. For non-transposing instruments (flute, oboe, violin, piano) these are the same. For transposing instruments (Bb trumpet, Eb alto sax, F French horn) they differ by the instrument's transposition interval.