There are different kinds of knitting needles. They come in different shapes, sizes and materials. When buying knitting needles, it is necessary to consider both the length and the diameter. To choose a particular type depends on the pattern, whether you want to knit flat or in the round. The important classifications of knitting needles are as follows:

• Single-point Needles
• Double-point Needles
• Circular Needles
• Cable Stitch Needles

Single-point Needles
These are the most common knitting needles. These knitting needles are straight, rigid and hence also known as Straight Needles. They are just a stick with a tapered end and the other end with some sort of stop, often a simple knob. The tapered end of the single-point needle is necessary to let you get the needle into an existing stitch. The stop keeps your knitting from running off the other end, allowing you to knit. These needles are used for making flat knit pieces in a wide variety of patterns. The needles consist of a long, pointed shaft, with a cap on which the size of the needle is usually indicated. Single-point needles are made of aluminum, steel, plastic, or various woods such as bamboo, rosewood, ebony, or birch.

Double-point or Double-Pointed Needles
These needles are made of similar materials like single-point needles. Double-point knitting needles are used in sets of at least four to create seamless circular items, such as tube socks, sleeves, or mittens. They are also used for flat items. The number of needles required is dependent on the circumference of the item being made. In knitting instructions, double point needles are often indicated as "dp". The needles come in different lengths. But unless they are very long, these needles are best suited to smallish pieces of knitting.

Circular Needles
Circular knitting needles usually consist of 2 short straight pieces, which are tapered at one end with the other ends joined by something flexible, usually a strong cylindrical piece of plastic. In other words, circular needles, usually made of flexible nylon "cord" with metal, plastic, or wooden tips, are used for seamless circular items that are too large to work comfortably on double-pointed needles. These needles can also be used for very large flat items. It is essential that the circumference of the piece being knit must be at least 2 inches or 5.08 cm larger than the length of circular needles. Accordingly, you can choose each needle type. Circular needles are available in various sizes, the length can be as small as 11" and as large as 47".

Cable Stitch Needles
These needles are the only knitting needles with a built-in bend, specially designed to keep the cable from slipping off. There are two types of cable stitch needles. One looks like a small hill in the middle of a long highway. It is called a straight cable stitch needle or a cable stitch holder. The other type of needle looks like a double-point needle with one end curved under. Each of these cable stitch needles comes in a larger and smaller size, sometimes referred to as bulky and regular.