Circular needles are great both for knitting in the round, and as replacements for single point needles. But if you're not used to them, there are a few things to bear in mind.
Circular needles have become ever more popular. Not only for knitting in the round where for larger items they can be much easier to use than DPNs, but also as a replacement for straight / single point needles. With these the weight of the project sits in your lap, rather than hanging off the needles under your elbows.
Circular needles have two sizes associated with them: length and size.
The size is the needle size - just like with any other knitting needle.
The length refers to the entire length from the tip of one tip to the tip of the other. This is the important length when knitting in the round because your project needs to go all the way around the loop of the needles without being stretched.
You can get away with shorter circular needles and bunch your stitches up. But, you can never get away with needles which are longer than the circumference of your project. Too long needles will mean you need to stretch the stitches to be able to knit them - and ruin your project!
If you're using them as alternatives to single point straight needles, then the length doesn't matter as much - just long enough to get all your stitches on, and not so long you have lots of cable getting in the way! Circular needles can be used to knit flat pieces, all you do is knit the row and when you get to the end, turn the piece around and start again!
So, circular needles are measured from tip-to-tip.If your project calls for a 60cm circular needle, you'll need a 60cm circular. This will consist of two tips (perhaps 10-15cm long each), and a cable of perhaps 30-40cm long.
Needle lengths tend to be standard for longer size circular needles (60cm and longer)
For shorter length circulars the tips get steadily shorter and shorter (and in some cases, bent, to follow the curve of the cable. This is because there needs to be a certain amount of cable between the tips in order for you to get a decent angle at the tips to make your stitches.
There are a huge range of lengths, sizes and materials - and we stock lots of them. If you have any questions, or need any support, just get in touch.