Craft Yarn Council (CYC) Standard Yarn Weight & WPI Chart
The universal standard classification system created by the Craft Yarn Council. Use this guide to identify unlabeled mystery yarn, choose appropriate crochet hook and knitting needle sizes, and verify gauge.
| Category | Type & Names | Wraps / Inch (WPI) | Yards / 100g | Rec. Hook Size | Rec. Needle Size |
|---|---|---|---|---|---|
| #0 | LaceFingering 10-count, Crochet Thread, Cobweb | 18+ WPI | 750 – 1,100 yds | Steel 6, 7, 8; Reg B-1 (1.6 – 2.25 mm) | US 000 – 1 (1.5 – 2.25 mm) |
| #1 | Super FineSock, Fingering, Baby | 14 – 18 WPI | 380 – 460 yds | B-1 to E-4 (2.25 – 3.5 mm) | US 1 – 3 (2.25 – 3.25 mm) |
| #2 | FineSport, Baby, 5-ply (UK/AU) | 12 – 14 WPI | 290 – 350 yds | E-4 to 7 (3.5 – 4.5 mm) | US 3 – 5 (3.25 – 3.75 mm) |
| #3 | LightDK, Light Worsted, 8-ply (UK/AU) | 11 – 15 WPI | 240 – 290 yds | 7 to I-9 (4.5 – 5.5 mm) | US 5 – 7 (3.75 – 4.5 mm) |
| #4 | MediumWorsted, Aran, Afghan, 10-ply (UK/AU) | 9 – 11 WPI | 180 – 220 yds | I-9 to K-10.5 (5.5 – 6.5 mm) | US 7 – 9 (4.5 – 5.5 mm) |
| #5 | BulkyChunky, Craft, Rug, 12-ply (UK/AU) | 7 – 8 WPI | 110 – 140 yds | K-10.5 to M-13 (6.5 – 9.0 mm) | US 9 – 11 (5.5 – 8.0 mm) |
| #6 | Super BulkyRoving, Chenille (Bernat Blanket), Super Chunky | 5 – 6 WPI | 65 – 85 yds | M-13 to Q (9.0 – 15.0 mm) | US 11 – 17 (8.0 – 12.75 mm) |
| #7 | JumboArm Knitting Roving, Extreme Bulky | 1 – 4 WPI | 30 – 50 yds | Q and larger (15 mm+) | US 17 and larger (12.75 mm+) |
How to Measure Wraps Per Inch (WPI)
- Find a ruler or wooden pencil: Any straight cylinder or standard ruler works.
- Wrap the yarn smoothly: Wrap the mystery strand around the pencil for 1 to 2 inches. Ensure the strands touch side-by-side without overlapping or stretching the fiber tightly.
- Count the strands in 1 inch: Count how many strands fit inside exactly 1 inch on your ruler.
- Match with the chart: If you count 9 to 11 wraps, you have #4 Worsted weight. If you count 14 to 18 wraps, it's #1 Fingering.
Fiber Density: Wool vs Cotton vs Acrylic
Remember that fiber density affects total yardage per 100 grams:
- • Wool & Acrylic: Lightweight and bouncy. A 100g skein of worsted wool typically delivers roughly 200–220 yards.
- • 100% Cotton & Linen: Dense and heavy cellulose fibers. A 100g skein of worsted kitchen cotton (like Lily Sugar'n Cream) typically contains only 150–160 yards.
- • Chenille & Polyester Blanket Yarn: Very thick plush core that weighs heavy per foot (~70–80 yds per 100g).
Have Mystery Yarn in Your Stash?
Pop it on your kitchen scale and use our interactive calculator to see how many yards you have left and what you can make!
Launch Yarn Yardage Calculator →