Which Needle Do I Use?
Knitting needles come in a range of sizes to suit various yarns. Sizes are usually identified by the U.S. number size or the metric conversion in millimeters—many patterns list both. The lower the number, the smaller the needle and the tighter the stitch. The most commonly used sizes are:
A knitting pattern will list a recommended needle size, but you may need to use a different size to obtain proper gauge. Make a gauge swatch using the recommended needle size, then adjust accordingly until you reach the right gauge.
In addition to different sizes (or thicknesses), knitting needles also come in three different styles: straight needles, circular needles, and double pointed needles.
Straight needles are pointed at one end and have a stop on the other end so your work does not fall off the needle. They are used in pairs for knitting back and forth in rows. They are available in 9", 10", 12", and 14" lengths in a range of sizes.
A circular needle is pointed on both ends with a long, flexible wire in the center. They are used for knitting in rounds when seams are to be avoided (sleeves, skirts, etc.). A circular needle can also be used to work back and forth in rows when the project has a large number of stitches that would not fit on a straight needle, such as for a knitted afghan. Circular needles are available in different lengths to suit different sized projects. A pattern will specify which length to use.