Bookmark our handy yarn weight conversion chart, explore the difference between DK and aran weight yarn and choose the right needles for your yarn. About to buy some yarn? Read this first! We'll explain why a yarn's weight has nothing to do with grams or kilos, as well as revealing what is meant by fingering, sport and worsted weight yarn. Plus we'll also teach you the basics of how to substitute yarns and help you choose the right yarn for your project with our yarn weight conversion chart.
When choosing the right yarn for your project, size matters. Knitting yarns come in a wide range of different thicknesses, or 'weights', and the weight of yarn you choose will have a big impact on the look and feel of your finished fabric.
To get the best results it's a good idea to use the weight of yarn specified in your pattern, although tools such as YarnSub can help if you want to find a substitute. Take care not to mix different weights of yarn in one project, unless it's a novelty look you're after! As a yarn's weight is determined by its thickness, a thin yarn such as lace is described as 'light', while a thick yarn such as super-chunky is 'heavy' — regardless of the overall weight of the ball.
Yarns come in a range of standard sizes the most well-known being set by the Craft Yarn Council , which can be found written on the ball band along with the suggested needle size and tension. You can find our guide to these weights below. Ply refers to the number of strands that are plied, or twisted together, during spinning to create a single strand of yarn. A 2ply yarn has two strands, a 3ply has three and so on. If you've ever untwisted or split your yarn while knitting, you'll have seen these individual plies.
Historically, yarn weights were named after these numbers, so the higher the ply the heavier the yarn, but today it's more complex than that.
