Wraps per inch (WPI)

As I've got quite a few odd balls of yarn I needed some way to find out what weight/thickness they were so I've made a reference table to help me:

UK	Wraps per inch
2ply	18+
3ply	16
4ply	14
Light DK	12
DK	11
(US worsted)	9
Aran	8
Chunky	6
Super Chunky	5 or less

To measure the wraps per inch, wrap your yarn around a large knitting needle/ruler/pencil and measure the wraps in an inch. The yarn should just be touching comfortably, not squashed together or spaced so that you can see the object underneath. As you can see from the picture on the left, the yarn used wrapped 10 times which makes this yarn a D.K./worsted weight.