If you need to quickly convert the tempo of a song, you can output a few types of data.

Different plugins ask for different information like ratio or percentage.  I’ve also included  “Time” options.

Use Cases:
1. If you have Original BPM, input Target BPM. Example Results:

Starting BPM: 123
Final BPM: 156
Ratio: 1.27
Percentage Change: 26.83%

2. If you have Original BPM and Track Time, you don’t care about final BPM but your plugin requires data other than Final Time (rare). Example 

Original BPM: 123
Original Time: 3:12
Target Time: 4:12
Final BPM: 93.71
Time Ratio: 1.31
Percentage Change: -23.81%

If your plugin asks for the “Original BPM” and “Final BPM” then you really dont need this tool.