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Yarn Weight Converter — US, UK & Metric Yarn Systems

Look up any yarn weight to see equivalent names across US, UK, and metric systems with needle, hook, and WPI data

Worsted

#4 / 10-ply / Aran

WPI

9–12

Yd/lb

800

Conversion

200 yd = 183 m
113 g (4 oz)
Needles
4.5–5.5mm
Hook
5.0–6.0mm

Full Weight Conversion Chart

USUK/AUWPIYd/lb
Lace (#0)1-ply / Cobweb30+2400
Fingering (#1)3-ply / 4-ply14–221600
Sport (#2)5-ply12–181200
DK (#3)8-ply / DK11–151000
Worsted (#4)10-ply / Aran9–12800
Bulky (#5)12-ply / Chunky7–9500
Super Bulky (#6)Super Chunky5–7300
Jumbo (#7)Jumbo / Roving1–5150

What You'll Need

KOKNIT Crochet Hooks Set 71pc with Storage Case

$16-$204.8
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HOMEST XL Yarn Storage Bag with Removable Dividers, Floral

HOMEST XL Yarn Storage Bag with Removable Dividers, Floral

$18-$254.6
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KnitIQ Blocking Mats 9-Pack Double-Sided with 100 T-Pins

KnitIQ Blocking Mats 9-Pack Double-Sided with 100 T-Pins

$25-$354.6
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36PCS Bamboo Knitting Needles Set 9 Inches

$7-$104.5
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Coopay Bamboo Crochet Hooks Comfort Grip Set

$14-$184.6
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Susan Bates Digital Row Counter

Susan Bates Digital Row Counter

$8-$124
View on Amazon

KOKNIT Crochet Hooks Set 71pc with Storage Case

$16-$204.8
View on Amazon
HOMEST XL Yarn Storage Bag with Removable Dividers, Floral

HOMEST XL Yarn Storage Bag with Removable Dividers, Floral

$18-$254.6
View on Amazon
KnitIQ Blocking Mats 9-Pack Double-Sided with 100 T-Pins

KnitIQ Blocking Mats 9-Pack Double-Sided with 100 T-Pins

$25-$354.6
View on Amazon

36PCS Bamboo Knitting Needles Set 9 Inches

$7-$104.5
View on Amazon

Coopay Bamboo Crochet Hooks Comfort Grip Set

$14-$184.6
View on Amazon
Susan Bates Digital Row Counter

Susan Bates Digital Row Counter

$8-$124
View on Amazon

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Example Calculations

1Worsted to UK Equivalent

Inputs

Yarn WeightWorsted (#4)
Yardage200 yards

Result

Equivalent10-ply / Aran
Meters183 m
Weight113 g

US Worsted #4 = UK 10-ply/Aran. 200 yd × 0.9144 = 183 m. At 800 yd/lb: 200/800 × 453.6 = 113 g.

2DK Yardage Conversion

Inputs

Yarn WeightDK (#3)
Yardage500 yards

Result

Equivalent8-ply / DK
Meters457 m
Weight227 g

US DK #3 = UK 8-ply/DK. 500 × 0.9144 = 457 m. At 1000 yd/lb: 500/1000 × 453.6 = 227 g.

Frequently Asked Questions

Q

How do yarn weight systems differ between US and UK?

The US uses category numbers (0–7) and names like worsted and bulky. The UK/Australia uses ply counts (4-ply, 8-ply, 12-ply). Both systems map to the same metric wraps-per-inch (WPI) measurements.

  • US Worsted (#4) = UK 10-ply / Aran
  • US DK (#3) = UK 8-ply / DK
  • US Fingering (#1) = UK 4-ply
  • US Bulky (#5) = UK 12-ply / Chunky
  • WPI is the universal measurement that works across all systems
Q

What is WPI and how do I measure it?

WPI stands for wraps per inch. Wrap yarn around a ruler or pencil for one inch without stretching or overlapping, then count the wraps. This gives you an objective yarn thickness measurement.

  • 9–12 WPI: worsted weight
  • 14–22 WPI: fingering / sock weight
  • 7–9 WPI: bulky weight
  • 5–7 WPI: super bulky weight
  • Measure on a flat surface, wrap snugly but not tight
Q

Can I substitute one yarn weight for another?

You can substitute within one weight category (e.g., different brands of worsted). Going up or down a weight requires recalculating yardage and adjusting hook/needle size to match the pattern gauge.

  • Same weight, different brand: usually works, swatch first
  • One weight up: need less yardage, larger hook, looser fabric
  • One weight down: need more yardage, smaller hook, denser fabric
  • Always swatch the substitution before starting a large project
Q

How many yards per pound for different yarn weights?

Yards per pound is the key number for comparing yarn value. Finer yarns have more yards per pound because the strand is thinner and lighter.

  • Fingering: ~1,600 yd/lb
  • DK: ~1,000 yd/lb
  • Worsted: ~800 yd/lb
  • Bulky: ~500 yd/lb
  • Super Bulky: ~300 yd/lb
  • Jumbo: ~150 yd/lb

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Last Updated: Mar 19, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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