Pistonsoft BPM Detector

This free audio tool scans your entire collection of songs and detects the number of beats per minute, which gives an idea of how calm or how energetic the tune is. Pistonsoft BPM Analyzer can display the numbers right away in its convenient browser-style interface, but most prefer this information saved as a tune's meta-tag. You'll end up having all of your MP3s with ID3v2 tags that contain BPM numbers - easy to access and show by your jukebox!