This is how you measure your size:

1) Place your foot on a sheet against a wall and draw the outline of your foot.

2) Measure from the tip of your longest toe to the end of your heel. 

Our tip: If you have rather small and narrow feet and a small instep, better take the smaller size, if you have wider feet with a high instep, choose the larger size. 

Important:

The foot length data is manually measured, the actual length may be 3mm-5mm gap