To know if a sandal will fit, cut a piece of string to length.
If the sandal is 20 inches measure a 40 inch string.
Take the listed size and double it. Match the ends of the string and loop the center of the string around your second toe. Cross the string and wrap around your ankle until the ends meet. The ends should be able to touch with enough slack for walking comfort.
Order custom barefoot sandals. Personalize with the colors you want and pre-measured for a perfect fit.