if there is a big difference, the measurement method is incorrect thank you for coming..syi put your foot on a piece of white paper, and use one pen to mark the longest points from front to back.the distance between two points is the correct length of your feet if high instep, wide and fat feet, it's recommended to choose a larger size; while flat instep, thin feet, please choose a smaller size than usual other items can be purchased according to the usual size the measured size should be almost the same as the usual.