The information​ on this page applies to the MP Select Mini V1 & V2

The following paragraph is an excerpt from Michael O'Brien's Hackaday project
Project: Monoprice Select Mini Electro-Mechanical Upgrades
Log: X, Y, Z, A Motors & Stepper Driver Investigation

Z-Axis Resolution

So that motor [Z-Axis] is a 7.5°, 48 step motor as I just listed. Since the motor is attached to a M4 rod, which has a 0.7 mm thread pitch, then in one revolution makes the Z-Axis travel up or down 0.7 mm. Since it took 48 steps to turn that rev, each step is 0.0145833333333333333333333333333 etc etc mm. To avoid rounding errors, you can use multiple of 3 of this number, which is a nice and pretty 0.04375 mm. That is a nice and handy number that effectively represents the layer heights that mathematically work the best for layer heights for this printer.

Using the information above we can put together a list of optimal layer heights ranging from 0.04375mm to 0.30625mm. We stop at 0.30625mm because with a nozzle diameter of 0.40mm, the maximum recommended layer height is 0.32mm.

PrusaPrinters.org - Optimal Layer Calculator
Triffid Hunter's Calibration Guide - Layer height, Extrusion width

* There have been a few reports of printing the same model at 0.04375 and 0.0875, with the 0.0875 version looking better. This is probably a settings issue and the reports could be outliers. Don't let this discourage you from trying to use 0.04375, you could and probably will have better results if you are patient enough to wait the extra time for higher resolution.