Most shoe insoles are designed such that one size insole will be compatible with 2-3 different sizes of footwear. For example, the Spenco Total Support Original Insoles
come in 7 different sizes (size #0–size #6) but these seven sizes will cover shoe sizes ranging from a Women's 3 to a Men's 15. For this example, if you wear normally wear a women's shoe size 7, you would choose the size #2 option for this insole, since that size insole corresponds with women's shoe sizes 7-8. Similarly, if you normally wear a men's shoe size 10.5, you would choose the size option #4 for this insole, since that size insole corresponds with men's shoe sizes 10-11.
Full-length insoles are often trim-to-fit, meaning that you may need to trim a portion of the insole to best fit into your footwear. If you purchase a full-length insole like the one in the example above, you may need to trim the insole if your typical shoe size falls on the lower end of insole's corresponding sizing (in the above example, the size #2 insole corresponds to a women's shoe size 7-8; if you typically wear a size women's 7 shoe, you will likely need to trim the insole to allow the best fit in your shoes). Always first try the insole in your shoe prior to trimming; you can always trim additional length off of the insole, but you can't add it back!
For our instructional video on how to trim your trim-to-fit insoles, please click here
3/4-length insoles, as well as inserts like ball-of-foot cushions or heel pads, generally do not require any trimming or modification to allow a proper fit. For these products, simply choose the size insole/insert that corresponds to the size footwear that you typically wear.
If you are in between sizes, we recommend that you go up to the next highest size.