Crochet Lesson: Understanding Gauge, Yarn & Hook Sizes

The fundamental concepts to understand when starting your crochet journey!


What is Gauge & How to Interpret Gauge Instructions

Gauge is the measurement of a specific number of stitches per row and rows per inch using a specific stitch, yarn and hook. It is essentially a reference swatch used to show stitch scale and desired tension within a particular project to help the crocheter achieve the correct sizing within their project. It also helps to determine the amount of yarn needed in a project.

Most crochet patterns suggest a gauge to ensure that your garment comes out in the correct size. Gauge can also be used to size up or down a garment. To make a design yourself, you’ll need to measure your gauge accurately and calculate the stitches and rows required to achieve your desired size. 

Understanding Gauge - 1

Gauge is read in stitches and rows on, commonly, a 4” x 4” swatch.

For example 9 stitches by 12 rows = 4” x 4” (10 cm x 10 cm) using a 5.5mm hook, which means that after you make your swatch in a 4” x 4” space you should have 9 stitches across and 12 rows crocheted for your piece to be the size desired.

You can usually find a suggested hook size for the particular yarn on the label of the yarn. But remember it is only a suggestion. You may need to go up or down a hook size to get the desired gauge for your project to be the correct size, as your personal tension will also come into play at this point. 

If your tension is looser than the gauge swatch (as in there are fewer stitches per row), use a smaller crochet hook.

If your tension is tighter than the gauge swatch (as in there are more stitches per row), use a larger crochet hook. 

TIP: Always make your swatch larger than the gauge swatch shown, as you want to measure the middle of your swatch where it is most consistent, not the edges, to obtain an accurate gauge. 


Tension is the tightness or looseness with which one crochets. It is based on the way you hold your yarn when crocheting, and how tightly you pull your stitches as you go. Your tension will affect the crochet gauge, which is something to keep in mind when sizing a pattern according to a gauge swatch. Tension can evolve over time, especially from the time that you first learn to crochet. The more you crochet, the more likely it is that you will develop a consistent tension. 

TIP: Once you become more advanced in crochet, when starting a project you may want to create your own gauge swatch and compare it to the sample, then adjust the pattern counts according to your gauge. This is an advanced crochet technique, so don’t worry about it when you’re starting out!

Understanding Hook Size - 2

Hook sizes

The hook size(s) given in a pattern are suggestions (see our note on sizing up or down your hook in the section on Gauge). On average, hook sizes range from 2.5 mm to 15 mm.

Hooks are most commonly made from one of the following materials: aluminum, steel, wood, bamboo, resin, or plastic.

Yarn Sizes

Yarn size (as in the width of a particular yarn) is actually called yarn weight and refers to the thinness or bulkiness of a yarn. Most yarn labels indicate a recommended hook size for that particular yarn weight.  When in doubt, you can refer to a Standard Yarn Weight Chart, such as this one from the Craft Yarn Council.

Yarn Weight & Hook Size Cheat Sheet:

  • Super Fine 1: 2.25—3.5mm
  • Fine 2: 3.5—4.5mm
  • Light 3: 4.5—5.5mm (Omegacryl and Favorito!)
  • Medium 4: 5.5—6.5mm
  • Bulky 5: 6.5—9mm
  • Super Bulky 6: 9—15 mm
  • Jumbo 7: 15mm and larger

TIP: Most crochet projects use lighter-weighted yarns to show the detail and intricacy of the pattern. But anything is possible! 

Understanding Yarn - 1
Understanding Yarn - 2

How to Find This Info on Yarn Packaging

Yarn packaging contains all the information you need to start a crochet or knitting project, including the yarn weight, length of yarn, suggested hook/needle size, fiber content, color and dye lot. Be sure to check your yarn packaging for this information to help determine how much yarn you’ll need for a project and the suggested hook size you’ll want to try.

When purchasing more than one skein of yarn for a particular project be sure to match the dye lot number--this ensures the skein came from the same batch of yarn and the shades will match exactly. 

Every ball of yarn has everything you need to create your project on the label. The brand, weight size, % of fiber content, length of yarn (grams/ounces & yards/meters), and color.

TIP: The label suggests needle and hook sizes as well as giving the gauge for 4” x 4” gauge in that suggested needle and hook size.

Crochet Care

Most crochet projects should be washed by hand and laid flat to dry, never hanging, as that will affect the shape of your work. Fold and store using tissue paper to protect from dust and heat.