360 degrees / degrees per step
360 / 1.8 = 200 steps per revolution

1/16 microstepping mean 16x the resolution,, but 16x the required pulses to move the same distance.

200 steps per revolution * 16x more steps = 3200 pulses to the stepper driver

16 tooth GT2 32mm per revolution
3200 / 32 = 100 pulses per mm

20 tooth GT2 40mm per revolution
3200 / 40 = 80 pulses per mm

T8x8 8mm lead screw 8mm move per revolution
3200 / 8 = 400 pulses per mm