Assuming the song sections are 8 are long (sometimes they are 16), you can calculate the length of song sections using this formula below.
In this case, we are assuming the music has 4 beats per bar, and each section is 8 bars long.
If a song has a tempo of 96bpm the calculation would look like this:
And each section would be 20 seconds long.
Note, if you want to look up the BPM of a Roblox MarketplaceAPM track, you need to go to the APM site, look up the track, and find its BPM there (see @jackjenningsdev’s post for instructions on how to look up a track on the APM website. There, in the track info, you’ll find the BPM).
Happy Looping, @kbcubezz !