2022 review update: super bummer. It does still work with some of my songs but not my playlist that I built, paid for all the songs, and downloaded onto my phone. No longer useful for my running. 2019 review: Was delighted to find this super simple option for matching songs I love to my ideal running cadence. I am happy at 162 bpm but several of my favorite running songs are 158 bpm. After a few days playing with different software including GarageBand, I stumbled across PerfectTempo! You do have to do a little math but it seems that 2% increase from my playlist is perfect. The interface is simple and familiar, and lets me access my playlist, any of my purchased albums, and Apple Music. It lists everything by song title but you can filter a little. So I set like 9 songs on a playlist, with a mix of original tempo and +2% tempo. The songs keep the choice I made, and there’s a toggle button to “repeat” or “off” or “repeat section”, but even when it’s off it still just plays the same song again. If it would go forward to the next song on the playlist, I’d like it better. As it is, I’ll have to mess around with my phone to manually choose the next song. Luckily they’re each pretty long!