Does exactly what it claims, perfectly.

I spend a lot of time combing charts and oldies for new music with the right bpm for walking, jogging, swimming and resistance training. It never even occurred to me that the tempo of tracks could be changed without complex remixing. This app has more than doubled my workout library. Successful tempo changes are limited by what sounds right to your own ear, generally within +/- 12% of the original bpm. Brilliant app!

Heif about Tempo Magic, v1.2.1