Understanding Yarn Weights and Plys: A Maker’s Guide to Getting It Just Right
- Caterina Sullivan
- Feb 25
- 4 min read
Whether you're a beginner who’s just discovered the joys of yarn craft or an experienced maker wanting to deepen your fibre knowledge, understanding yarn weights and plys is one of the most useful tools in your crafting toolkit. The right yarn weight can make or break a project; it affects everything from the drape and structure of your final piece to how long it takes to complete and how much yarn you’ll need.
Let’s untangle the mystery and make it simple, so you can choose your yarn with confidence every time.
What Is Yarn Weight? (And Why It Matters)
Contrary to what the term might suggest, 'yarn weight' doesn’t refer to how heavy a skein is. It refers to the thickness of the yarn strand itself. Yarn weight determines the size of your stitches, the drape of your fabric, how warm the finished item will be and what size needles or hooks you’ll need.
Yarn weights are typically grouped into standard categories ranging from laceweight (very fine) to jumbo (very thick). Let’s walk through the most common yarn weights you’ll encounter:
Common Yarn Weights (From Thinnest to Thickest)
Best for: Holding together with another yarn, Shetland lace scarves
Texture: Delicate, light
Needle/Hook Size: 1.5mm–2.25mm
Best for: Delicate shawls, lacy wraps, heirloom projects
Texture: Light, airy, floaty
Needle/Hook Size: 1.5mm–2.25mm
Note: Often used with large needles for open, airy fabrics
Best for: Socks, lightweight tops, baby garments
Texture: Fine but strong
Needle/Hook Size: 2.25mm–3.25mm
Note: Great for colourwork and detailed patterns
Best for: Baby clothes, hats, lightweight jumpers
Texture: Slightly thicker than fingering, soft and flexible
Needle/Hook Size: 3.25mm–3.75mm
Best for: Garments, blankets, homewares
Texture: Versatile, smooth fabric with good drape
Needle/Hook Size: 3.75mm–4.5mm
Note: One of the most popular weights
Best for: Winter garments, hats, scarves
Texture: Warm, dense, holds shape well
Needle/Hook Size: 4.5mm–5.5mm
Best for: Cozy jumpers, blankets, fast projects
Texture: Thick, warm, textured
Needle/Hook Size: 5.5mm–8mm
Note: Great for beginners who want quicker results
Best for: Statement scarves, thick throws, floor cushions
Texture: Super chunky and squishy
Needle/Hook Size: 9mm and above
Note: Very fast to work up and full of texture
What Is Ply, and How Is It Different from Weight?
Now, here’s where it can get a little confusing. In Australia, we often use ply as a measurement, while internationally, weight is more common. While they’re often used interchangeably, they’re not quite the same thing.
Ply originally referred to the number of strands twisted together to make a yarn. For example, a 4-ply yarn had four individual threads twisted together. However, thanks to modern spinning techniques, a yarn’s ply count doesn’t always correspond to its thickness. You can now find thick 2-ply yarns or thin 8-ply yarns depending on how they’re spun.
So, while ply can be a helpful guideline, especially when shopping in Australia or the UK, it’s always best to check the yarn label for the recommended needle size and stitches per 10cm square. That’ll give you the most accurate information about its actual weight.
At Fancy Yarns Australia, we use yarn weight and the American naming system as we find it a little less confusing when talking about a 3-ply (3 strand) fingering yarn than a 3-ply 4ply yarn. (See what we mean!?)
How to Match Yarn Weight to Your Pattern
Choosing the right yarn weight is crucial to making sure your project turns out as expected.
Here’s how to get it right:
Follow the pattern’s recommended weight
If your pattern calls for DK yarn, substituting it with bulky yarn will dramatically change the size, structure and feel of your project.
Check the tension/gauge
Most patterns include a gauge measurement (e.g. 22 stitches and 30 rows = 10cm in stockinette stitch). Swatching will help ensure your chosen yarn and needle size match the designer’s intended fit and drape.
Consider fibre type and spin
Even within the same weight category, fibre type affects drape and structure. For example, a bamboo DK yarn will drape more fluidly than a wool DK yarn. A chainette-spun yarn (like Tulla Tweed) will behave differently from a traditional plied yarn.
Tips for Substituting Yarn Weights
Substituting yarn in a pattern? Here’s how to do it thoughtfully:
Match weight and gauge as closely as possible
Use similar fibre types to get the same drape and texture
Compare metres per 50g or 100g between your substitute and the original
Always swatch first to check size and feel
Don’t forget to consider washing instructions and yarn care
Understanding yarn weights and plys gives you the confidence to explore patterns, try new fibres and make the most of your crafting time. Whether you're diving into a laceweight shawl or grabbing a chunky yarn for a quick-knit beanie, knowing your yarn means better results and a more joyful process.
At Fancy Yarns Australia, we stock a diverse range of yarns across multiple weights. Each yarn comes with full fibre details and recommended uses to help you choose with confidence.
Still unsure? We’re always happy to help match you with the right yarn for your project. Just reach out, and we’ll help untangle the options!
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