BPM ÷ 60 × note duration

Step 1: BPM/60

(? / 60)  x ? = Notes Per Second

? = BPM

? = quarter notes per second

Step 2: if you have…

Eighth notes (1/8) – multiply by 2
Triplet eighth notes (1/12) – multiply by 3
Sixteenth notes (1/16) – multiply by 4
Triplet sixteenth notes (1/24)  – multiply by 6
Thirty-second notes (1/32)  – multiply by 8
Triplet thirty-second notes (1/48) – multiply by 12

Example: Through the Fire & Flames red snake is 32nd notes

Formula: (200/60)*8=26.66nps

Breakdown

take 200 (beats per minute)

…divide by 60 (seconds)

… multiply by 8 (quarter notes per second)

= 26.6666 notes per second