These follow standard European women's sizing. Note that the material is stretchy and doesn't shrink, so no need to pick a larger size "just in case".
In the chart below are theactual measurements taken directly from the garment, NOT user's recommended sizes. Note that these are meant to stretch, so they may look small.
Centimeters
Size | Chest | Waist | Back length | Sleeve
X-Small | 66 cm | 50 cm | 67 cm | 70 cm
Small | 74 cm | 58 cm | 68 cm | 70,5 cm
Medium | 82 cm | 66 cm | 69 cm | 71 cm
Large | 90 cm | 74 cm | 70 cm | 71,5 cm
X-Large | 100 cm | 82 cm | 71 cm | 72 cm
2X-Large | 112 cm | 96 cm | 72 cm | 72.5 cm
Inches
Size | Chest | Waist | Back length | Sleeve
X-Small | 26" | 19.5" | 26.5" | 27.5"
Small | 29" | 23" | 26.5" | 27.5"
Medium | 32.5" | 26" | 27" | 28"
Large | 35.5" | 29" | 27.5" | 28"
X-Large | 39.5" | 32.5" | 28" | 28.5"
2X-Large | 44" | 38" | 27" | 28"
The measurements might have a tiny bit of tolerance (a centimetre or so) from shirt to shirt, just because stretchy material is harder to sew consistently. The garment does form to the body, so this really is a non-issue.