How to Size Your Superfeet              
Every shoe manufacturer has their own sizing, which can be very confusing. One brand's size 8 is not necessarily another brand's size 8. Many people wear shoes that are too small or too big because they don't know what size they truly are. To help avoid this confusion and preoccupation with size, Superfeet identifies each of their product sizes with letters. Each letter represents approximate sizing based on the footwear industry's manufacturing scale. Here is a quick way to size your Superfeet.
Step 1                  
Check the Superfeet sizing chart, and select the letter you feel is the closest to your shoe size.    
  J A B C D E F G H
MEN'S   5.5-7 7.5-9 9.5-11 11.5-13 13.5-15 15.5-17
WOMEN'S   4.5-6 6.5-8 8.5-10 10.5-12  
KID's 11.5-13 13.5-2 2.5-4  
Step 2                  
If the insole you selected is too short, go up one size.            
Step 3                  
Check the heel width. If the insole is too narrow, go up one size.          
Step 4                  
Follow the Quick Start Trim and Fit instructions below.            
Trim and Fit Your New Superfeet Insoles          
The way you trim your insoles can have a great effect on how well they will work and feel. For an ideal fit, follow these simple steps:
Step 1                  
Remove the insole that came in your shoe. To work properly, your Superfeet insole should lie on the bottom surface of your footwear. It should not rest on any additional insole, arch pad or heel cushion material. These items should be removed.
Step 2                  
Place the original insole over the top of your new Superfeet insole, lining up both the heel and inside edge. With a marking pen, trace the original insole pattern onto the new Superfeet insole. Trim the insole by cutting along the inside edge of the tracing line. Care should be taken not to trim too short. Trim it, try it. Trim it, try it.
Step 3                  
Fit your insole into your footwear, resting it properly on the bottom. The insole needs to have minimal back-to-front movement inside the footwear (about 1/16" or 2mm) to ensure the insole moves with your foot and is not jammed heel-to-toe. This is very important. Properly trimmed, your insoles will fit easily into your footwear without a struggle, and will not curl up in the toe area.  
If You Have No Original Insole                
If there is no original insole in your footwear to use as a template, place your footwear over your new Superfeet insole, and trace an outline around the toe area. Then follow the usual trimming instructions. Hint: trace and trim one insole first, then use it as a template for the second insole.
Too Tight in the Forefoot                
If your footwear is too tight to accommodate the full length of your Superfeet insole, you can trim off the forefoot closer to the stabilizer cap. This will have no effect on the biomechanical benefits of the insole.