For wide feet, we recommend going up a half size. Each half size is only 4mm longer and you get the extra width. So, if you typically wear a 10EE then you would order a 10.5D.For narrow feet, the recommendation really comes down to the length of your foot. Going down a half size only shortens the boot by 4mm, but brings in the width. Combining this with a thick pair of socks usually does the trick.