If you normally wear a whole size: Order the same whole size OOfos.
If you normally wear a half size:
Revolutionary OOfoam technology absorbs 37% more impact than traditional footwear foam materials to reduce the stress on your feet and joints. The OOmg features a breakthrough in shoe construction that eliminates unnecessary layers and leaves only OOfoam between your foot and the ground. New OOtex 4-way stretch mesh upper conforms to your feet and the stretchable strap adds support over the arch without binding. These technologies combine to aid in the recovery process and create an incredibly comfortable shoe you can wear anywhere.