Crochet Yarn & Hook Size Guide – Complete Reference
Choose the right yarn & hook with total confidence 🧶
The most common question new crocheters ask is "which yarn and hook size should I use?" This complete guide explains yarn weights, crochet hook sizes (mm, US and UK), the best yarn for amigurumi, gauge, and exactly what to buy — so every project starts right.
What does "yarn weight" actually mean?
Despite the name, yarn weight has nothing to do with how heavy a ball of yarn is. It describes the thickness of the strand. Thicker yarn makes larger stitches and works up quickly; thinner yarn makes finer, more delicate stitches. The Craft Yarn Council (CYC) sorts yarn into eight standard categories, numbered 0–7, that crocheters use worldwide. Knowing your weight is the single most important step in choosing materials, because it determines your hook size, how much yarn you need, and the size of the finished piece.
Standard yarn weight chart (CYC 0–7)
| CYC # | Yarn weight | Also called | Common uses | Typical hook |
|---|---|---|---|---|
| 0 | Lace | Fingering 10-count, thread | Doilies, lacework, fine shawls | 1.5–2.25 mm |
| 1 | Super Fine | Fingering, Sock, Baby | Socks, baby garments, fine detail | 2.25–3.5 mm |
| 2 | Fine | Sport, Baby | Baby items, light accessories | 3.5–4.5 mm |
| 3 | Light | DK, Light Worsted | Amigurumi, garments, toys | 4.5–5.5 mm |
| 4 | Medium | Worsted, Aran, Afghan | Amigurumi, blankets, bags, décor | 5.5–6.5 mm |
| 5 | Bulky | Chunky, Craft, Rug | Hats, baskets, chunky accessories | 6.5–9 mm |
| 6 | Super Bulky | Super Chunky, Roving | Cozy blankets, statement pieces | 9–15 mm |
| 7 | Jumbo | Roving, Arm-knitting | Arm crochet, oversized projects | 15 mm+ |
Most beginners start with a medium / worsted (CYC 4) yarn because it's easy to see, easy to handle and widely available — a perfect match for the patterns in our beginner collection.
Crochet hook size conversion chart (mm · US · UK)
Crochet hooks are measured in millimetres, but US brands also use a letter/number system and the UK uses its own numbers. Here's the full conversion so any pattern makes sense:
| Metric (mm) | US size | UK size | Best for |
|---|---|---|---|
| 2.25 mm | B-1 | 13 | Fine amigurumi, thread work |
| 2.75 mm | C-2 | 12 | Amigurumi with DK yarn |
| 3.25 mm | D-3 | 10 | Amigurumi, tight stitches |
| 3.5 mm | E-4 | 9 | Amigurumi, small toys |
| 3.75 mm | F-5 | — | Worsted amigurumi |
| 4.0 mm | G-6 | 8 | Worsted toys, beginners |
| 4.5 mm | 7 | 7 | Garments, soft toys |
| 5.0 mm | H-8 | 6 | Blankets, bags, beginners |
| 5.5 mm | I-9 | 5 | Bags, chunky toys |
| 6.0 mm | J-10 | 4 | Blankets, home décor |
| 6.5 mm | K-10½ | 3 | Chunky accessories |
| 8.0 mm | L-11 | 0 | Bulky blankets |
What hook material should I choose?
Hook size affects your stitches; hook material affects your comfort. Aluminium hooks are smooth and let yarn glide (great all-rounders). Ergonomic hooks with soft, cushioned handles are kindest on your hands during long sessions — well worth it if you crochet for hours or have wrist strain. Bamboo and wooden hooks have a little more grip, which some makers prefer for slippery yarns. There's no single "best" — pick what feels good in your hand.
Best yarn for amigurumi: cotton vs acrylic
Amigurumi is one of the most popular forms of crochet, and the yarn you choose changes the whole look and feel of your toy. The two most common choices are cotton and acrylic — here's how to decide:
| Cotton yarn | Acrylic yarn | |
|---|---|---|
| Stitch definition | Crisp, sharp, shows detail beautifully | Softer, slightly fuzzier definition |
| Feel | Firm, structured, holds shape | Soft, squishy, cuddly |
| Budget | Pricier | Very affordable, widely available |
| Best for | Detailed, display-worthy figures | Kids' toys, beginners, big projects |
Our recommendation: cotton for crisp, collector-style pieces; acrylic for soft, cuddly, budget-friendly toys and for beginners. Whichever you pick, choose a DK (CYC 3) or worsted (CYC 4) weight and a hook one to two sizes smaller than the label suggests. The smaller hook makes tight stitches so the stuffing never peeks through.
Want to put it into practice? Every design in our amigurumi collection lists the ideal yarn and hook, so you can shop with zero guesswork.
What is gauge — and does it matter?
Gauge (also called tension) is simply the number of stitches and rows that fit within a measured square, usually 10 cm × 10 cm (4" × 4"). It tells you whether your fabric will come out the same size as the designer's.
- For garments, bags and wearables — matching the pattern's gauge matters, because it directly affects the finished size. Always make a small gauge swatch first.
- For amigurumi — exact gauge is less important. Instead, aim for a firm, even fabric with no gaps between stitches. If you can see stuffing through your work, go down a hook size.
How to fix common tension problems
If your stitches are too loose and gaps appear, switch to a smaller hook or hold your yarn a little firmer. If your work is too tight and hard to hook into, go up a size or relax your grip. Consistency matters more than being "tight" or "loose" — aim for the same tension on every stitch. New to controlling tension? Our skill level guide points you to forgiving beginner projects to practise on.
How to substitute yarn in a pattern
Don't have the exact yarn a pattern calls for? You can usually substitute another yarn of the same CYC weight. Check the yardage (metres/yards per ball), not just the gram weight, so you buy enough. For amigurumi you have lots of freedom; for fitted garments, make a gauge swatch in your substitute yarn first to confirm the size.
Beginner materials checklist
Before starting your next crochet project, make sure you have:
- ✔ Yarn in the weight specified by your pattern
- ✔ The recommended crochet hook size (plus one size up and one down for adjustments)
- ✔ Stitch markers (a lifesaver for working in the round)
- ✔ Sharp scissors
- ✔ A yarn or tapestry needle for weaving in ends and seaming
- ✔ Polyester fibre stuffing (for amigurumi)
- ✔ Safety eyes or embroidery thread for faces
- ✔ A row counter or notepad to track your rounds
That's everything a beginner needs. As your skills grow you'll discover your favourite yarn brands and hook styles — but you can start beautiful projects today with this simple kit.
Tips for first-time crocheters
If you're completely new, don't agonise over finding the "perfect" yarn or hook. Choose a beginner-friendly pattern, follow its recommended materials list exactly, and focus on learning the basic stitches. Pick a smooth, light-coloured yarn so your stitches are easy to see, and a comfortable hook in the size your pattern calls for. Work in good light, count your stitches as you go, and remember that uneven tension is completely normal at the start — it evens out with practice. The best crochet project is simply the one you enjoy making, so be kind to yourself and pick something that makes you smile. Once a few makes are under your belt, you'll naturally develop preferences for the yarns, hooks and techniques that suit you best.
How to read a yarn label (ball band)
Every ball of yarn comes with a label — sometimes called a ball band — packed with the information you need to crochet successfully. Learning to read it takes the guesswork out of shopping. Look for these details: the weight category (often shown as a number 0–7 inside a little yarn-skein symbol), the fibre content (for example "100% cotton" or "100% acrylic"), the yardage and grams per ball (so you can work out how many balls you need), the recommended hook size (a useful starting point, though for amigurumi you'll usually go smaller), the care instructions (machine washable or hand-wash only — important for baby items and toys), and the dye lot number. That last one matters: balls from different dye lots can vary very slightly in colour, so buy all you need for a project from the same lot. Once you can read a ball band at a glance, you can confidently substitute yarns and plan any project.
Common yarn fibres explained
Beyond weight, the fibre a yarn is made from changes how your project looks, feels and wears. Here are the fibres you'll meet most often and when to reach for each:
| Fibre | Feels like | Best for | Watch out for |
|---|---|---|---|
| Acrylic | Soft, springy, lightweight | Beginners, kids' toys, blankets, big projects on a budget | Can pill over time; "squeaky" on metal hooks |
| Cotton | Firm, smooth, structured | Amigurumi detail, bags, dishcloths, summer wear | Less stretch; can be harder on the hands |
| Wool | Warm, elastic, forgiving | Hats, garments, anything you'll block to shape | Many wools need hand-washing; can itch |
| Cotton-acrylic blend | Smooth but with a little give | Amigurumi and toys — the best of both | Quality varies by brand |
| Chenille / velvet | Plush, ultra-soft | Cuddly toys, baby blankets | Slippery; stitches hide — tricky for beginners |
| Bamboo / blends | Silky, drapey, cool | Lightweight wearables and shawls | Can split; needs an even tension |
For most makers starting out, a smooth acrylic or a cotton-acrylic blend in worsted weight is the easiest, most affordable and most forgiving choice. Save the slippery velvet and splitty bamboo for once your tension is steady.
How much yarn do I need?
The amount of yarn a project needs depends on its size, the stitch used and the yarn weight. Taller stitches and thicker yarn cover more ground per yard, so they use less. As a rough planning guide in worsted weight:
- Small amigurumi (a palm-sized toy): 50–150 yards
- Large amigurumi or a bag: 200–400 yards
- Baby blanket: 700–1,000 yards
- Throw blanket: 1,800–2,400 yards
- Adult sweater: 1,000–1,500 yards
- Beanie hat: 150–250 yards
Always check the yardage printed on the ball band (not just the gram weight) and buy one extra ball from the same dye lot so colours match if you run short. Every MrsCrochetWorld pattern tells you exactly how much yarn to buy.
How to hold your hook and yarn
Comfort and even tension start with how you hold things. There are two common ways to hold a crochet hook: the pencil grip (holding it like a pen) and the knife grip (holding it like a table knife). Neither is "correct" — try both and keep whichever feels natural. To control tension, run the working yarn loosely through the fingers of your non-hook hand so it feeds smoothly and evenly. If your stitches are uneven at first, don't worry: tension settles with practice, usually within your first project or two. Choosing a forgiving beginner pattern makes this learning curve much gentler.
Frequently asked questions
What size crochet hook should I use for amigurumi?
Most amigurumi uses a 2.5–4.0 mm hook with DK or worsted yarn — about one to two sizes smaller than the yarn label suggests. The smaller hook makes tight stitches so stuffing doesn't show.
What is the best yarn for beginners?
A smooth, light-coloured medium/worsted (CYC 4) acrylic yarn. It's affordable, easy to see and forgiving — perfect for learning. Avoid dark, fuzzy or novelty yarns at first.
Is cotton or acrylic better for amigurumi?
Cotton gives crisp stitch definition and a firm, display-worthy finish; acrylic is softer, cheaper and more beginner-friendly. Both work well — choose based on the look and feel you want.
What hook size is a 5 mm in US terms?
A 5.0 mm hook is a US size H-8 (and UK size 6). See the conversion chart above for the full mm-to-US-to-UK breakdown.
Does yarn weight mean how heavy it is?
No. Yarn weight refers to the thickness of the strand, not the weight of the ball. The Craft Yarn Council numbers run from 0 (lace) to 7 (jumbo).
How do I stop stuffing showing through my amigurumi?
Use a hook one to two sizes smaller than the yarn label recommends to create tighter, gap-free stitches, and stuff firmly but evenly.
Do I always have to match gauge?
For garments and anything fitted, yes — gauge controls the finished size. For amigurumi, exact gauge is less important; just aim for a firm fabric with no visible gaps.
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