The measurements are given in CM. The blond model on the images is 166 cm and uses x-small. Her measurements are: Waist circumference - 65 cm, hip circumference - 94 cm, inseam length - 70 cm.
If you are in between two sizes, you should choose the larger one. The fabric is stretchy but with compression so they should fit really tight when you put them on and then they shape to your body as you use them.
If you are still not sure about what size to pick or have any questions about the fit or the products, please send us an email at email@example.com and we will help you further!