My daughter's foot is 6 1/2 inches or 17 cm and she wears size 10 street shoes. Based on reviews I ordered her slippers 1 size up and received her size 11C and they fit perfectly! She has a narrow foot, but the "C" fits her perfectly and she still has room to grow. Very well made shoes and they should keep them.
Capezio Girls 3800 Mary Jane Tap Shoe in Caramel - Size 11.5 M Toddlers
49 Review
Flexible Comfort: pediped Flex Isabella Mary Jane for Toddlers and Little Kids
47 Review
Slip-Resistant Crib Shoes for Babies: Robeez Soft Soles for Girls and Unisex Toddlers, Ages 0-24 Months
53 Review
Dance in Style with Molly Jane Tap Shoes: Unisex-Child Mary Flats
50 Review