Music is all about time. Using a delay calculator to get your beats to be represented in exact milliseconds is crucial. The calculation is quite simple, but a tool like this can help you visualize the delay times for each timing division in your project. For example, you will be able to see divisions from 1 bar all the way down to a 1/128 note including quarter notes, half notes, and the rest!.
To calculate delay times by hand, you just need to divide 60,000 by your BPM. There are 60 seconds in 1 minute (need reference), which equates to 60,000 milliseconds in one minute. Dividing this number by your BPM will, thus, give you the value of a quarter note in milliseconds.