You should follow our sizing chart to ensure correct sizing. For best results take a barefoot measurement from heel to largest toe and compare to our size chart. You can find help for how to measure your feet here: colours-sizes. If this method is impossible, for example if you are purchasing a surprise gift, then we recommend you take the usual size. If you are in between sizes, we would encourage you to take the size up. For example if you are normally a Ladies 6.5, we would recommend purchasing a Ladies 7. Your barefoot measurement in this instance would be between 23.6 cm to 24.5 cm. When creating sizes and designing patterns, we have already taken into consideration the density of the wool. If you are not sure, you are always welcome to contact us for assistance.