When you go to pick out your first set of knitting needles, the variety can seem overwhelming. Your pattern probably calls for a specific type of needle—straight, circular, or double-pointed. If it does not, or even if it does, it helps to know how to use each type, and when one can be substituted for another.
This needle type is pointed on one end with a stop or guard on the other. It is used for “flat” or back-and-forth knitting. Most beginner patterns use this type of needle.
This needle has two pointed ends at the appropriate needle size, connected by a flexible cable. The cables come in various lengths.
Circular needles (not to be confused with cable needles, though they have a cable) can be used for knitting flat or in the round. When knitting in the round, you would only ever knit from one side to the other, no turning required. In this case, try to choose a cable length that is approximately the same or slightly shorter than the circumference of your project. If your cable is too long, that’s okay—you can still use it by pulling the excess length of cable in a loop out between stitches. You will continually have to do so as you work around your project, however.
Some projects which are knit flat are too large and bulky for straight needles, which are usually no longer than 14 inches/35 cm. (Think afghans, large cardigans knit in one piece, etc.) In that case, you can use circular needles. Choose a very long cable, at least 40”/100 cm, and simply treat the two ends as though they were straight needles. E.g. Work your first row, then turn the work as you would for straight needles and work your way back.
These needles have points on both ends and range in length from 4”/10 cm to 9”/22.5 cm. They are used for knitting in the round, and come in sets of at least four—three for holding your stitches and one for working your next stitches onto.
Double-pointed needles (dpns) can also be used as flat needles for very small projects that are shorter than the length of the needle (such as a gauge swatch.)
This needle can be shaped like a hook or a double-pointed needle with a bend in it. It is used for holding stitches away from the main work when creating cables and texture stitches. If you need this type of needle, your pattern should say so.
Needles can be made from plastic, wood, bamboo, or metal. Each material feels different to work with, “grabs” yarn differently, and makes different amounts of noise as you work. The type of needle you use will mostly be based upon availability and personal preference. For most projects, I prefer wood or bamboo needles because they are quieter and have a little more friction than metal (so the stitches do not slip off when I don't want them to) and they feel nicer than plastic, plus they are not as easily bent. I do not recommend metal needles for beginners, as stitches tend to slip off of them very easily.