Size Description: 6.5 US = 24.00 cm (Foot Length) = 9.45 inch 7 US = 24.50 cm (Foot Length) = 9.65 inch 7.5 US = 25.00 cm (Foot Length) = 9.84 inch 8 US = 25.5 cm (Foot Length) = 10.03 inch 8.5 US = 26.00 cm (Foot Length) = 10.23 inch 9.5 US = 26.50 cm (Foot Length) = 10.43 inch 10 US = 27.00 cm (Foot Length) = 10.62 inch 10.5 US = 27.50 cm (Foot Length) = 10.82 inch 11 US = 28.00 cm (Foot Length) = 11.02 inch Inner length=feet length+(0.5~1.0cm) 1cm=2.54inch Friendly Reminder: It will feel more comfortable if your feet length is shorter than insole length about 0.19 - 0.80in.