WPI Calculator
Identify the weight of unlabelled mystery yarn by counting how many times it wraps around 1 inch of a ruler.
How to measure: Wind the yarn around a ruler or pencil snugly (not stretched, not loose) for 1 inch. Count the number of wraps. That's your WPI.
WPI Reference Chart
| WPI Range | Yarn Weight | US Needle | Metric (mm) |
|---|---|---|---|
| 30+ WPI | Lace | US 000–1 | 1.5–2.25mm |
| 22–30 WPI | Fingering / Sock | US 1–3 | 2.25–3.25mm |
| 16–22 WPI | Sport | US 3–5 | 3.25–3.75mm |
| 12–16 WPI | DK | US 5–7 | 3.75–4.5mm |
| 9–12 WPI | Worsted | US 7–9 | 4.5–5.5mm |
| 6–9 WPI | Bulky | US 9–11 | 5.5–8mm |
| Under 6 WPI | Super Bulky | US 11+ | 8mm+ |