Measure Both Feet. One foot is usually slightly larger than the other foot. Sometimes the difference is negligible but, in some instances, it can differ by a half or even full size. Buy the shoe size that fits the larger foot. There are a variety of shoe pads and inserts that can fill out a shoe if it is too big, but you cannot add space to a shoe that is too small. Some high end shoe stores, such as Nordstrom’s, will sell you a pair of shoes that are two different sizes.
Stand when measuring. Be sure to stand up when measuring your feet. When standing, your feet will spread out more. It is better to have someone else take the measurement, because you need to stand tall and look straight ahead with your weight centered over your foot. How you stand can affect the size and shape of your feet.
Don’t get hung up on shoe size. There are big differences in shoe sizes between shoe companies. So, just because your last pair of Ferragamo’s was a size 8 doesn’t mean a pair of Jimmy Choo’s will be an 8. This is especially prevalent in women’s shoe styles and designers. Don’t get hung up on thinking your feet are too big if you wear a size 9. Take care of your feet — the shoe that fits, and looks great, is the shoe you want, regardless of the size on the inside.
Fit the arch properly. An important part of the shoe fit is the arch length. The arch length is measured from your heel to the ball of your foot (where your big toe joint bends). The bend in your big toe should match with where the shoe bends. With both shoes on, rise up onto your toes. If you feel the shoe bend before or after the big toe joint, then the shoe is not a good fit for your arch length.
Leave space at the front and back of shoe. The toes need room to move. Not having enough room for your toes may lead to corns, calluses or deformed toes. Be sure you have enough room to wiggle your toes. There should be about a 1/2 inch (length of the tip of your index finger) between the end of your longest toe (not always your big toe) and the end of the front of the shoe.
Your heel should fit comfortably in the shoe with a minimum amount of slipping – the shoes should not ride up and down on your heel when you walk. You do not want the back of the shoe too tight against the back of your heel. This may cause skin irritation and blisters. It is OK to have about a 1/8 of an inch between the back of your heel and the shoe.