How to easily calculate the Beats Per Minute (BPM) of a song

Knowing the  Beats Per Minute (BPM) of a song can be very useful

• If you are a runner matching the BPM to your running pace can help improve your performance.
• Professional DJ's need to be able to blend the end of one song into the next, without the transition being awkward or jerky. By figuring out the BPM  you'll  know if you need to bring the tempo up or down to have them both playing at the same speed.
• Creating a  playlist to fit a certain mood is considerably easier if you use songs with a similar BPM

But how do you actually calculate it ?

There is now a really easy way to do this thanks to a new project called  AcousticBrainz 
a collaboration between MusicBrainz and Music Technology Group, University of Barcelona

• First your songs needs to have MusicBrainz Recording Ids, as you know this is easiest to do by running them through SongKong Tagger 
• Then download an AcousticBrainz client from here
• Install and run the client and point it to your music collection, this will calculate the BPM for each song and then submit it anonymously to AcousticBrainz
• Then to look up the BPM just look up the page http://acousticbrainz.org/mbid in your web browser i.e. http://acousticbrainz.org/5f3a763a-669d-4a4c-bafa-d76fc5ae885d
• You'll notice it doesn't just provide the BPM but all kind of cool things such as key, danceability and mood , but more about these in another post.

The future

This is a brand new project so it is not integrated into any other tools yet but soon SongKong and Jaikoz will allow you to both submit new AcousticBrainz data and to automatically add it to your songs.