Key Transposition Calculator — Transpose Music Keys
Transpose chords and notes between musical keys by any number of semitones.
Positive = up, negative = down
How We Calculate This
Each note is assigned a number (C=0, C#=1, D=2... B=11). To transpose, add the number of semitones and take the result modulo 12.
New note index = (original index + semitones) mod 12
Frequently Asked Questions
Related Calculators
BPM Calculator
Tap to detect BPM or convert between beats per minute and milliseconds per beat. Free online tempo detection tool for musicians and DJs.
Interval Calculator
Find the musical interval between any two notes with semitone count, frequency ratio and cents. Free interval calculator for musicians.
Chord Calculator
Build chords from any root note and view the notes, intervals and frequency ratios. Free online chord building calculator for musicians.
Scale Calculator
Generate musical scales from any root note including major, minor, pentatonic, blues and modal scales. Free online scale calculator.
Tempo Calculator
Convert BPM to note durations in milliseconds for setting delay, reverb, LFO and other tempo-synced effects. Free online calculator.
Last updated: February 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.