Tempo-Pitch Transposition Calculator
Calculate the pitch change in cents and semitones when audio is played back at a different speed or tempo (BPM). Used in DJ mixing, time-stretch analysis, and tape speed calculations.
Results
What is it?
When audio is played back at a different speed (without time-stretching), pitch changes proportionally. The relationship is logarithmic because pitch perception is logarithmic: a doubling of frequency is one octave (1200 cents). The formula cents = 1200 � log2(newBPM/oldBPM) converts speed ratios to musical pitch units, as log2(x) = ln(x)/ln(2).
How to use
Enter the original tempo and the new playback tempo. If using varispeed (analog tape, vinyl turntable pitch control), the pitch shifts by the amount shown. If using a DJ controller's key lock/master tempo feature, the tempo changes while pitch stays fixed. Use this calculator to predict pitch shift without key lock or to find the pitch correction needed.
Example scenario
A DJ beatmatches a 120 BPM track to a 128 BPM mix (6.67% speed increase). Without key lock, the pitch rises by 110.7 cents � just over 1 semitone. Listeners with trained ears will notice this as a key change. The DJ can use pitch correction to shift the 128 BPM version down 110.7 cents to restore the original key.
Pro tip
The human pitch detection threshold is approximately 5�10 cents � below this, pitch shifts are imperceptible. Most CDJ/DJ controllers with key lock introduce artifacts above �5�8 semitones due to the limits of phase vocoder time-stretch algorithms. For cleaner pitch shifting, use the Elastique algorithm (found in Rekordbox, Serato, and Ableton Live).