The Ultimate Crochet Hook Size Guide: Choosing the Right Hook for Your Project

One of the first decisions you’ll make when starting a crochet project is selecting the right hook size. The size of your hook determines the size and tension of your stitches, which in turn affects the overall look and feel of your finished piece. Even though this is a guide, there is no right or wrong size hook! Of course if you are following a pattern you will want to use the size hook they use in the pattern to achieve the same look. Sometimes I will use a bigger crochet hook to make my project lighter and airier. Or sometimes I will use a smaller one to make it look chunkier. 

 With so many different hook sizes available, it can be overwhelming to know where to start. That’s why we’ve put together this comprehensive guide to help you navigate the world of crochet hook sizes with ease. If you are looking for a good pack of crochet hooks to get yourself started I would recommend this package right here. Also, these crochet hooks are designed to make your hands hurt less while doing stitches which is a big plus.
If you’re a complete beginner make sure you check out my complete beginner’s guide to crochet here!

1: Understanding Crochet Hook Sizes

Crochet hooks come in a wide range of sizes, usually indicated by a letter or a number. The size of the hook determines the size of the stitches and the thickness of the yarn it’s designed to work with. Of course, It can be confusing to see a whole bunch of measurements and numbers. Just know that there are different systems, you usually don’t have to convert back and forth. Luckily, most crochet hooks say both the metric and US sizes right on them. Here’s a breakdown of common crochet hook sizes:

1. Metric Sizes: These are designated by millimeters (mm) and are commonly used in most countries outside of the United States. For example, a 5mm hook is suitable for medium-weight yarn.
2. US Sizes: In the United States, crochet hooks are often labeled with letters ranging from B (2.25mm) to S (19mm).
3. UK Sizes: In the UK, crochet hooks are labeled with numbers, with larger numbers indicating larger hook sizes.

2: Choosing the Right Hook Size

Selecting the correct hook size is crucial for achieving the desired outcome in your project. Remember this is just a guide. There is no fully right or wrong answer here but here’s a general guide of what’s recommended.  So, Here’s how to choose the right hook size:

1. Yarn Weight: Match the hook size to the weight of your yarn. Use a smaller hook for finer yarns and a larger hook for thicker yarns.
   • Fine Yarn (Fingering, Lace): Use a small hook size, such as 2.25mm to 3.5mm.
   • Light Yarn (Sport, DK): opt for a medium-sized hook, around 3.5mm to 5mm.
   • Medium Yarn (Worsted, Aran): A hook size between 5mm and 6.5mm works well.
   • Bulky Yarn (Chunky, Super Bulky): Use a larger hook, such as 6.5mm to 9mm.
2. Project Type: Consider the type of project you’re working on. Delicate lacework may require a smaller hook, while a cozy blanket may need a larger one. This is where you can play around with the way you want your fabric to flow as well. 
3. Gauge: Pay attention to the gauge specified in your pattern. If your stitches are too tight, use a larger hook; if they’re too loose, use a smaller hook. Remember it’s always helpful to make a gauge patch if you’re not sure. That way you can count your stitches!
4. When in doubt start with what the yarn package says: All yarns come with a recommended crochet hook/knitting needle size guide. Although it may not be exactly what you want to use, it can be a good starting point to try. Below I’ve shown where to look on the package for it.

3: Common Crochet Hook Sizes

Here are some common crochet hook sizes and their recommended uses:

1. 3.5mm (E/4): Ideal for fine yarns and delicate projects like lacework and amigurumi.
2. 5mm (H/8): A versatile hook size suitable for medium-weight yarns and a wide range of projects, from hats to scarves. Size H and size I,  I personally find are the most versatile! If you are wondering what hook size to buy to just start out. This is a pack of just H, and I size If you just want the basic ones and don’t want a whole package of crochet hooks.
3. 6.5mm (K/10.5): Great for bulky yarns and quick projects like blankets and Afghans.
4. 8mm (L/11): Perfect for super bulky yarns and chunky projects, such as cowls and oversized sweaters.
5. 15.75mm (Q) Great size for wool, and super bulky sized yarns. When I use bulky yarns I use this size the most.

4: Crochet Hook Conversion Chart

Converting between metric, US, and UK crochet hook sizes can be confusing. Here’s a handy conversion chart to help you:

• 2.25mm (B/1) – 14
• 2.75mm (C/2) – 12
• 3.25mm (D/3) – 10
• 3.5mm (E/4) – 9
• 3.75mm (F/5) – 9
• 4mm (G/6) – 8
• 4.5mm (7) – 7
• 5mm (H/8) – 6
• 5.5mm (I/9) – 5
• 6mm (J/10) – 4
• 6.5mm (K/10.5) – 3
• 7mm – 2
• 8mm (L/11) – 0
• 9mm (M/13) – 00
• 10mm (N/15) – 000
• 12mm (P/16) – 15
• 15mm (Q) – 19
• 16mm (S/19) – 19

Choosing the right crochet hook size is essential for achieving the perfect tension and stitch definition in your projects. By understanding the relationship between hook sizes, yarn weights, and project types, you’ll be ready to tackle any crochet project with confidence.

Next time you’re starting a new project, refer back to this guide to select the perfect hook size for your needs. Happy crocheting!