A Beginner’s Guide to Yarn Weights
Like I mentioned in my previous guide, this post will be about the thickness of yarns. Yarn weight is one of the most important things to understand when choosing yarn for a knitting or crochet project. It affects how your finished piece looks, feels and fits. Many beginners think yarn weight refers to how much the yarn weighs in grams, but in reality it describes the thickness of the yarn. Thicker yarns create larger stitches and work up faster, while thinner yarns create finer and more delicate fabrics.
Understanding yarn weight makes it easier to follow patterns, choose the right needles or hook and avoid common beginner mistakes.
What Are Yarn Weights?
Yarn weight refers to the thickness of the yarn, not its physical weight. It determines how large your stitches will be, how dense or airy the fabric feels and which tools you should use. Using the wrong yarn weight can completely change the size and look of a finished project, even if you follow the pattern exactly.
Yarn Weight Chart (UK & US)
Below is a simple overview of the most common yarn weights and how they are typically used. Here you have both the UK yarn weight chart and the US.
Lace (0)
Very fine yarn used for delicate projects.
Best for: lace shawls, lightweight scarves
Skill level: advanced
Fingering / 4 Ply (1)
Thin yarn with excellent stitch definition.
Best for: socks, baby clothes, lightweight garments
Skill level: beginner to intermediate
Sport / DK (2–3)
One of the most versatile yarn weights.
Best for: sweaters, cardigans, hats, baby items
Skill level: beginner-friendly
DK yarn is often recommended as the best starting point for beginners.
Worsted / Aran (4)
Medium-thick yarn that works up quickly.
Best for: jumpers, blankets, accessories
Skill level: beginner-friendly
Aran is commonly used in UK knitting patterns.
Chunky / Bulky (5)
Thick yarn with bold, visible stitches.
Best for: scarves, hats, cosy winter projects
Skill level: beginner-friendly
Super Chunky (6)
Very thick yarn for oversized and statement projects.
Best for: blankets, oversized knits
Skill level: beginner
Which Yarn Weight Is Best for Beginners?
For most beginners, DK or Aran yarn is the best choice. These yarn weights are easy to handle, show stitches clearly and are forgiving of small mistakes. They are also widely used in beginner-friendly knitting and crochet patterns.
Very thin yarns can feel slow and frustrating, while very thick yarns may hide technique issues and make it harder to learn proper tension.
Yarn Weight and Needle or Hook Size
Each yarn weight works best with a specific range of needle or hook sizes. Using needles or hooks that are too small or too large can change the drape and size of your project.
Always check:
- the pattern recommendations
- the yarn label
- your gauge by making a small swatch
Swatching helps ensure your finished project turns out the right size.
Can You Substitute Yarn Weights?
Yarn weights can sometimes be substituted, but this should be done carefully. Small substitutions, such as using Sport instead of DK, are often possible if you adjust your needle or hook size and check your gauge.
Larger substitutions, such as replacing DK with Chunky, can dramatically change the final result and are not recommended unless you are intentionally redesigning the project.
Common Yarn Weight Mistakes
Some of the most common yarn weight mistakes include choosing yarn based only on colour, ignoring the pattern’s recommended yarn weight, skipping the gauge swatch and assuming all yarns behave the same.
Taking a few minutes to understand yarn weight can save hours of reworking later.
Final Thoughts
Understanding yarn weights makes knitting and crochet much more enjoyable. Once you know how yarn thickness affects your project, following patterns becomes easier and choosing yarn feels far more confident.
For a complete introduction to yarn selection, including fibre types and colour tips, read our guide on how to choose the perfect yarn for your next project.
