To measure the length and width of your feet, all you have to do is to step on a piece of paper and draw the outline of your foot with a thin, body and tip, pen or pencil, making sure to hold it as vertical as possible to the ground, as tilting it either way might not give the correct results. For optimal results and accuracy, ask someone to outline your feet for you. Then measure the widest and longest points of the traced outlines, as the images below show.
Your left and your right foot measures could be different. Chose the biggest one.
Send me an email with 1) the measures in cm, 2) a photo of the drawing, and 3) your usual fit, at email@example.com and I will find the right fit for you.