You have a sample and want to know its new tempo after altering the pitch.
You have a sample and want to know how much to alter its pitch to reach a certain tempo.
I originally created this tool because I wanted a pitched-up vocal effect free from time-stretch artefacts and needed to calculate what tempo to record in. Say I have a track in 140 BPM and want to record vocals to be pitched up by 3 semitones, then I'd enter—using the left column—140 in the first field and -3 in the second, resulting in 117.725.
What this means is if you record your vocals 3 semitones down at 117.725 BPM, throw it into a sampler and pitch it back up by same amount, it will arrive at precisely 140 BPM.
The formula to calculate the resulting tempo of a sample after altering its pitch looks as follows
where Tempo1 denotes the tempo before the change, Tempo2 the tempo after the change and k the change in semitones.
Subsequently, you can calculate the change in semitones given two tempo values