Things You'll Need
Crochet slippers come in a variety of shapes and sizes, but some patterns appear to be one-size-fits-all or they come with directions for only one size. If you want to resize a crochet slipper pattern to fit someone you know, simply change a few things about the slipper's construction and you will be able to make your crochet slippers in any size you need.
Change the yarn you use. If the pattern calls for a light, fingering-weight yarn, for example, you can make your slippers larger by using a worsted-weight or bulky yarn. A pattern calling for a thick yarn can be made smaller simply by switching to a thinner yarn.
Change the size of the crochet hook. Using a larger hook will make larger stitches, which will result in a larger sized slipper. Using a smaller hook will make smaller stitches and a smaller slipper. As long as you can still comfortably use the yarn called for in the pattern, you can change the size of the slipper you make by changing the size of the hook. This method works best if you make only minor changes--one or two hook sizes different from the one called for in the pattern.
Change the number of stitches. Most crochet slipper patterns begin at the sole, where you crochet an oval shape to fit the wearer's foot, then crochet in the round to make the sides and top of the slipper. To change the size of the slipper, change the size of the oval. Start your beginning chain with fewer stitches and then your oval will be smaller; add stitches to the starting chain to make it larger.
Combine methods to drastically alter a pattern. To make a pattern significantly smaller, use a lighter-weight yarn, a smaller hook, and fewer stitches in the starting chain. To make a pattern significantly larger, use a thicker yarn (or two strands held together), a larger hook, and add chain stitches to the beginning chain.