Do ask for shoes measurement when placing order for more accurate size. Furthermore, different shoes have different cuttings.
Shoes Measurement Guide
1. You need a piece of paper larger than your foot, a pencil, tape and a ruler or measuring tape.
2. Tape the paper down to the floor.
3. Trace the outline of your foot and remember to measure your foot without shoes. (with socks if you'll be wearing with the shoes)
4. Use your pencil to draw straight lines touching the outermost points at the top, bottom, and both sides of the outline.
5. Use your ruler or measuring tape to measure the length from the bottom line to the top line.
6. Do measure in centimeters as the measurements I give will be in centimeters.
Credits to http://shoes.about.com/
