First, we drew up a 20 3mm x 20mm rectangles inside a larger rectangle.
Then we exported and cut it out at speed = 37 mm/s speed and power 85% on the XTool.
To measure the kerf, we placed all 20 rectangles back in and measured the gap created after the cut with a caliper.
The result was 8.15 mm.
Then, we divided this number by 20 because there are 20 rectangles, and then again by 2 because the kerf is on both sides.
The result was a 0.204 mm kerf.