I learned my way around a crochet hook when I was 6 or 7 years old, but it took some time for me to figure out why crochet hook sizes mattered. As far as I was concerned then, the funkier the crochet, the better. Size may not matter in regards to your personal life…but it sure does when crocheting!
My grandma has been a crochet expert for as long as I can remember. If you wanted a new pair of mittens, or you know, anything else, you always asked grandma if she could crochet it for you! She taught me all I know. Aren’t grandmas great?
First off, to adequately gauge what kind of size needed, you need to know the different crochet hook sizes! Did you know there are over 17 different sizes of crochet hooks? Here are their size conversions in meters, knitting needle number, and crochet hook size. Use this chart below to get familiar with the different crochet hook sizes:
Crochet Hook Sizes Conversion Chart
| Diameter-in Meters | Knitting Needle Number-United States | Crochet hook size |
| 16 mm | n/a | Q |
| 25 mm | 50 | U |
| 19 mm | 35 | S |
| 15 mm | 19 | P/Q |
| 12.75 mm | 17 | |
| 10 mm | 15 | N/P-15 |
| 9 mm | 13 | M/N-13 |
| 8 mm | 11 | L-11 |
| 6.5 mm | 10.5 | K-10.5 |
| 6 mm | 10 | J-10 |
| 5.5 mm | 9 | I-9 |
| 5 mm | 8 | H-8 |
| 4.5 mm | 7 | 7 |
| 4 mm | 6 | G-6 |
| 3.75 mm | 5 | F-5 |
| 3.5 mm | 4 | E-4 |
| 3.25 mm | 3 | D-3 |
| 2.75 mm | 2 | C-2 |
| 2.25 mm | 1 | B-1 |
Crocheters should be aware that many companies use their own alphabet to categorize the hook sizes or just a different form of measurement altogether. That being said, when buying a new crochet hook, I would recommend ignoring any other classification and just focusing on the size in millimeters (mm).
Crochet Hook Sizes For Yarn
Why Does Crochet Hook Size Matter?
At this point, you’re probably wondering, why does crochet hook size matter? It matters because the size of your crochet hook affects the finish of your project! The bigger the hook= the looser the stitch, the looser the finish. Additionally, if you come back to a project later, using a different crochet hook size, you’ll run into some difficulty joining the pieces together.
When working with a crochet pattern, always create a pattern gauge as a guide for hook size (I like to use this tutorial). Before beginning, crochet a sample swatch so you can adequately decide what your hook size should be. If your sample swatch is bigger than the pattern gauge, try it again with a smaller hook until you get it right. If it’s too small, retry it with a larger hook. A pattern gauge is your best friend, and using it will really affect your crochet projects for the better!
