How to harmonize pitch with tempo

Here’s a useful tool to help composers harmonize the musical notes of a song with the tempo of that same song.

The numbers are written in beats per minute. The piano keys refer to the pitch that best harmonizes with that tempo. So, for example, a song written in 81.8503 bpm is most harmonious with the note F.

This chart assumes A is equal to 440 hz, tuned with equal temperament.