A needle is a thin, pointed tool with an eye at one end for holding thread. Sewing needles are usually steel, polished smooth to slide through fabric without snagging. They come in numbered sizes. A size 60/8 is fine for lightweight cotton. A size 100/16 handles denim and canvas. The wrong needle leaves holes, breaks thread, or bends on the first stitch.

Knitting needles look different. They are longer, with a point at one end and a cap or second point at the other. They are sized by diameter in millimetres or by old US and UK numbers. Circular needles join two tips with a flexible cable, which makes knitting in the round easier. Double-pointed needles come in sets of four or five for small tubes like socks and mittens.

Specialty needles exist for almost every fiber craft. Tapestry needles have a blunt tip and a large eye for yarn. Embroidery needles are sharp with a long eye. Leather needles have a triangular point that cuts through hide. Beading needles are thin enough to pass through tiny seed beads. A good needle is not expensive, but it is not disposable either. Cheap ones bend, rust, or leave burrs that fray thread. Buy a few good sizes and keep them dry.