Size Chart:

US6-6.5: Ball Girth: 3.4", Foot Length: 9.3", Shoes Inner length: 9.8"

US7-7.5: Ball Girth: 3.5", Foot Length: 9.6", Shoes Inner length: 10.2"

US8-8.5: Ball Girth: 3.7", Foot Length: 10.0", Shoes Inner length: 10.6"

US9.5-10: Ball Girth: 3.8", Foot Length: 10.4", Shoes Inner length: 11.0"

US11-11.5: Ball Girth: 3.9", Foot Length: 10.8", Shoes Inner length: 11.4"

US12-12.5: Ball Girth: 4.0", Foot Length: 11.2", Shoes Inner length: 11.8"

US13-14: Ball Girth: 4.1", Foot Length: 11.6", Shoes Inner length: 12.2"

US14.5-15: Ball Girth: 4.3", Foot Length: 12.0", Shoes Inner length: 12.6"

This data was obtained from manually measuring the product, it may be off by 1-2 CM