100mm square and 50mm circle calibration (XY calibration)

thingiverse

Measure a printer's ability to create precise angles and rounded shapes with this straightforward test. A square should be exactly 100mm by 100mm in size, while a circle must have a diameter of 50mm. To verify accuracy, cross-measure the distance between opposite corners - it should equal 141.42mm if the line is straight. This model's thickness is 2mm, but you can print only one layer to get an accurate reading.