YarnCalculator
Identify a yarn

Wraps per inch (WPI) calculator

No label, no problem. Wrap the yarn around a pencil or ruler, count the wraps in an inch, and this tells you which yarn weight it most likely is.

Enter the wraps you counted to see the yarn weight.

Wraps per inch by yarn weight
Yarn weightWraps per inch
0 · Lace30–40
1 · Super Fine (fingering, sock)14–30
2 · Fine (sport)12–18
3 · Light (DK)11–15
4 · Medium (worsted, aran)9–12
5 · Bulky (chunky)6–9
6 · Super Bulky5–6
7 · Jumbo1–4

Craft Yarn Council ranges. They overlap, so swatch to be sure.

Wraps per inch chart: WPI ranges for each yarn weight, from lace to jumbo
Wraps per inch chart: WPI ranges for each yarn weight, from lace to jumbo. Free to print and save.

How to use it

  1. Wrap the yarn around a pencil or ruler, each wrap touching the last, without stretching it or overlapping.
  2. Wrap at least 2 inches (5 cm) for bulky yarn, then count the wraps.
  3. Enter the wraps and how many inches you wrapped. The weight it fits shows instantly.

Questions

What does WPI mean in yarn?

WPI is wraps per inch: how many times a yarn wraps around a pencil in one inch, laid side by side. Thinner yarn gives more wraps, so the count tells you the yarn weight.

Why does my WPI fit more than one yarn weight?

The usual WPI ranges overlap, because how tightly you wrap changes the count and yarns of the same weight differ in loft. Use the closest match, then knit or crochet a gauge swatch to be sure.

How many wraps per inch is worsted weight?

Worsted (medium, weight 4) is usually 9 to 12 wraps per inch. DK is 11 to 15, and bulky is 6 to 9.

How do I measure WPI in centimeters?

Wrap 2.5 cm and count, or wrap 5 cm and halve the count. One inch is 2.54 cm.

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