Yarn Weight Converter
Convert between UK, US and Australian yarn weight names with recommended needle sizes, hook sizes, wraps per inch and typical gauge for each weight.
Select Yarn Weight
Wraps Per Inch
32+
Needle Size
1-3 mm (US 000-1)
Hook Size
1-2 mm
Typical Gauge
32+ stitches per 10cm
Lace
Extremely fine, delicate lace weight yarn
Wraps Per Inch (WPI)
The number of times a yarn wraps around a ruler in one inch. Higher WPI means finer yarn. Use this as a quick reference if you don't have official specs.
Needle & Hook Sizes
These are starting recommendations. Always check your pattern and knit a gauge swatch to find the right size for your project.
Gauge
The number of stitches and rows per 10cm. Lighter yarns create more stitches in the same space, heavier yarns create fewer.
Quick Reference Table
| Weight | WPI | Gauge (per 10cm) | Needle (mm) |
|---|---|---|---|
| Lace | 32+ | 32+ stitches per 10cm | 1-3 |
| Fingering / Superwash | 28-32 | 28-32 stitches per 10cm | 2-3 |
| Fine / Sport | 22-26 | 22-26 stitches per 10cm | 3-4 |
| Light / DK (Double Knit) | 18-22 | 18-22 stitches per 10cm | 3.75-4.5 |
| Medium / Worsted | 16-20 | 16-20 stitches per 10cm | 4.5-5.5 |
| Bulky / Chunky | 12-16 | 12-16 stitches per 10cm | 5.5-8 |
| Super Bulky | 6-12 | 6-12 stitches per 10cm | 8-12.75 |
About yarn weights
Yarn weight determines how thick the yarn is and how many stitches you'll knit per 10cm. Heavier yarns create quick projects, while lighter yarns are perfect for intricate stitch patterns and fitted garments. Always check your pattern for specific gauge and needle size recommendations.
Yarn Weight Categories
Standard yarn weight categories (CYC - Craft Yarn Council numbering): 0 Lace, 1 Super Fine (Fingering), 2 Fine (Sport), 3 Light (DK), 4 Medium (Worsted/Aran), 5 Bulky (Chunky), 6 Super Bulky, 7 Jumbo. Each category has typical needle/hook sizes and gauge (stitches per inch). UK and US use different terminology - UK 'Aran' = US 'Worsted'; UK 'Chunky' = US 'Bulky'.
Wraps Per Inch (WPI) is another measure - wrap yarn loosely around a ruler and count wraps per inch. Lace = 18+ WPI. Fingering = 14-16 WPI. Sport = 12-14 WPI. DK = 11-12 WPI. Worsted = 9-11 WPI. Bulky = 6-9 WPI. Super Bulky = 5-6 WPI. Different yarns within the same category vary; WPI gives a more precise classification than category alone.
UK to US Translation
UK 4ply ≈ US Fingering/Sport. UK DK = US DK (consistent). UK Aran = US Worsted (about 8-9 stitches per inch on US7/4.5mm). UK Chunky = US Bulky (about 5-6 stitches per inch on US10/6mm). UK Super Chunky = US Super Bulky. The DK category is the most consistent globally; other categories shift between systems.
Pattern ambiguity: a 'DK' pattern works similarly in UK and US. An 'Aran' pattern from UK source = Worsted yarn in US, NOT 'Aran weight' (which doesn't exist in US system). When buying yarn for a UK pattern, look for 'Aran' or 'Worsted' label - either works. UK Patons Diploma DK and US Knit Picks Brava DK should produce similar gauge.
Picking Yarn for a Project
Match yarn weight to recommended on pattern. Substitution within same weight category usually works (different yarn brand, same Worsted weight). Fibre matters too: cotton drapes differently from wool, acrylic from silk. Weight is the gauge anchor; fibre changes drape, warmth, and care. Check pattern's recommended yarn for both weight AND fibre.
Common project weights: socks = Fingering or Sport. Baby blanket = DK or Worsted. Adult sweater = Worsted or Aran. Throw blanket = Aran or Bulky. Quick scarf = Bulky or Super Bulky. Lace shawl = Lace or Fingering. Mixing weights in a single project creates uneven drape - usually avoided unless intentional design choice. Use the [Stitch Counter](/stitch-counter) for tracking project progress.
Substituting Yarn
Same weight category = usually safe substitution. Adjust needle size if necessary to hit the pattern's gauge. Always make a gauge swatch (4×4 inches in pattern stitch) before starting. Different from pattern gauge by 1-2 stitches per 4 inches = noticeable size difference in finished project. Adjust needle size up/down by 0.5-1mm to fix gauge.
Yardage calculation: pattern says '500 yards Worsted' - your substitute yarn lists yards per ball. Buy enough balls to hit 500 yards plus 10-20% buffer for seam allowances and unexpected mistakes. Solid colours are usually replaceable; multi-colour or speciality yarns (variegated, gradient) can be harder to substitute exactly. Match colour and texture as well as weight.
Frequently Asked Questions
What's gauge?
Number of stitches and rows per inch (or 4 inches/10cm) you produce with specific yarn and needle/hook. Pattern gauge is what the designer used; matching it ensures correct sizing. Make a 'gauge swatch' before starting - 5+ inches square, in the pattern stitch.
Can I always substitute one yarn for another?
Within same weight category, yes for most projects. Different fibres affect drape, warmth, washability. Different colourways affect striping/speckling. Always make a gauge swatch even with similar yarns - tension varies between brands and individuals.
What about UK 'double knitting' vs DK?
Same thing. 'Double knitting' is the full UK term; 'DK' is shorthand. Confusion sometimes arises with 'double knit' (a knit-fabric structure technique, not a yarn weight). Check context.
What's lace weight for?
Very fine yarn (similar to embroidery thread). Used for delicate shawls, doilies, lacework. Knit on small needles (US 1-3 / 2.25-3.25mm). Final fabric is light, airy, drapey. Not suited to warm garments; often blocked aggressively to open up lace patterns.
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