When I crochet slippers I like to have a thick sole so that my feet won't hurt when walking around the house, especially in areas where there aren't carpets. Searching the Internet, I found a practical guide for different shoe sizes and I used it with a slight change in the pattern. You can find the guide attached on pdf.

In this Instructable, I made a slipper sole size 7.

Step 1: Crochet Soles Easy Peasy...!

First of all, you need to measure the foot. I made these soles for making slippers for my brother, and I needed 25cm length and 10cm width soles, but I chose to make the length 3cm further just in case my brother's feet will grow in the next months...! ( He's still in his developmental age....) ^_^

After measuring, I decided what size to do and looked at the table in pdf for instructions. I used a hook size of 6.5mm and two colors of yarns to make the sole more thick. If you want to make just one color, simply use a thick yarn.

Below I explain abbreviations so you can read the pattern more easily ( I used the US terminology):

CH : Chain

ST : Stich

SD : Single crochet

HDC : Half double crochet

DC : Double Crochet

SLST : Slip stich

When I place numbers after the abbreviation this means the number of stiches, i.e. SC14 means you have to single crochet for the next 14 stiches.

I remind you to see the pdf for sizes, because you need to chain stiches differently based on the size. I made size 7 like this:

CH24
SC3 into 2nd ST of the chain
SC14, HDC3, DC4 and DC7 in the last ST (make 7 double crochet in the same stich which is the last)
Working on the opposite side of the chain (turn your work): DC4, HDC3, SC14 and place a marker (this will help you later to track your stiches). The next steps are increasing steps.
SC2 into each of the next 3STs and then SC22
SC2 into each of the next 5STs and then SC22
For the next 6Sts you have to SC1 and SC2 in the same next ST. Then SC22
For the next 10STs you have to SC1 and SC2 in the same next STs. Then SC22
For the next 6STs SC2 in each ST and then SC22
For the next 10STs SC2 in each ST and then SC untill marker
Finally, SC around untill you reach the marker again.

In step 11 I didn't do any further increase because the sole wasn't turn out the way I liked, so I simply SC around to smooth the edges.

Measure your sole and make sure it's the size you need.

If you have any question or doubt feel free to ask!

Have a good crocheting...! ^_^