What Are Measures Per Minute?
There are different ways of measuring tempo. Although beats per minute (bpm) are more common, "measures per minute" (somtimes "bars per minute") are the dominant tempo measurement among dancers. They are also used in official competition guidelines.
You can change the displayed tempo to mpm on your Dashboard.
Tempo Conversions
On this site, the Spotify API is used to add tracks. Because it supplies the tempo of a track in bpm, the measures per minute are automatically calculated. This calculation is made either according to the time signatures of the respective dances (Waltzes) or to match the most commonly Spotify-supplied bpm range to the mpm range of competition guidelines.