Calibration test on XYZ for ender 3 for cube and circle.
Cube external side measure: 20mm
Cube internal side measure: 18mm
Cicle diameter: 20mm
Note, is not reccomended to use nozzles > 0.4 mm (is better use a 0.2 mm nozzle). X, Y and Z letters of the cube should not be calculated by the slicer but is possible to see a little piece on the "Z" side, however it shouldn't be a problem for the printer.