A karate uniform, otherwise known as a gi (pronounced "gee"), is a specialised outfit designed for toughness and flexibility. A gi is typically made of a rougher or harder fabric that allows the wearer to kick and punch in a full range of motion with little or no restriction--something common clothing often does not afford. The gi is a robe-like outfit that is made up of three parts: the jacket, the trousers and the belt. Often, the colour of the belt distinguishes a student's rank. Karate uniforms are often purchased; however, it is possible to make your own.
Decide how many uniforms and you want to make and for what purpose. Do you want to make a children's uniform or an adult's? Is this for actual karate use or for a costume?
Purchase the fabric to fit your needs. Strong, heavy fabric should be used for professional use and lighter fabric for a costume or other use. Typically, heavy cotton or a polyester/cotton blend is used.
Purchase a gi pattern. Be clear whether you are buying an actual gi pattern or simply a gi costume pattern. The lighter costume won't stand up to the demands of martial arts practice.
Measure the person who will be wearing the gi with for his chest, waist and hips. Measure his arm length when it is extended (the reach of your punch standing up) and leg length as well, from the hips to slightly below the ankles (also known as the out seam).
Cut the fabric to the pattern size according to your measurements. Stitch the gi together with a sewing machine using durable thread and strong stitching patterns. Go back over the stitching multiple times to ensure strength and durability. Be sure to layer the stitching at least three times.
Try the uniform out. The wearer should do some stretches and warm up and kick and punch to test for flexibility and ease of motion. Adjust as needed.
If you use quality fabric and the wearer is fit and quick, the uniform should "snap" or make a cracking sound like a whip when she punches or kicks at sufficient speed. If in doubt, cut more material than you think you would need, not less. You can always cut away fabric, but you can't reattach it.
Do not buy cheap material to save money. The weaker material simply will not hold up long enough to make it worth your money.