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

$${\mathrm{Tempo}}_{2}={\mathrm{Tempo}}_{1}\times {2}^{\frac{k}{12}}$$where *Tempo _{1}* denotes the tempo before the change,

Subsequently, you can calculate the change in semitones given two tempo values

$$k=12\times {\mathrm{log}}_{2}\left(\frac{{\mathrm{Tempo}}_{2}}{{\mathrm{Tempo}}_{1}}\right)$$