Sometimes you need a lightweight top to wear outside in warm weather, but you get cold when you come inside to an air-conditioned environment. Or you might be warm during the day but cool at night after the sun goes down. These situations call for a shrug, which is a lightweight jacket that is essentially just an extra pair of sleeves with a back. Slide it on over a tank top or other lightweight top for an extra layer of warmth without a lot of extra bulk. Use simple sewing techniques to make a shrug jacket with any length for the sleeves.
Stand with your arms stretched out at your sides, making a "T" with your body. Enlist the help of a partner to measure your wingspan, from wrist to wrist for a long-sleeved shrug jacket or from elbow to elbow, upper arm to upper arm for a three-quarter length or short-sleeved shrug. This is measurement A. Measure around the widest part of your forearm; this is measurement B. Measure from your wrist (or elbow, or upper arm; wherever you started measurement A) to your armpit, on the underside of your arm; this is measurement C.
Cut a length of fabric that is as long as measurement A, plus 5 cm (2 inches). Measure the width to be as wide as measurement B, plus 5 cm (2 inches). Fold in the top and bottom long edges by 1.25 cm (1/2 inch) each, and sew a hem. Fold in the short edges 1.25 cm (1/2 inch), then 1.25 cm (1/2 inch) more, and sew a hem.
Fold the fabric lengthwise so that the long edges meet with the right sides facing. Sew a hem 1.25 cm (1/2 inch) in from the top edge of the fabric moving from the outside right edge to the centre. Make this hem the same length as measurement C. Repeat this step, working from the outside left edge to the centre. Now your shrug is inside-out.
Turn the shrug right-side out. It will resemble a long tube with a hole in the middle. That hole is where your back goes; slide your arms through either side of the tube and wear your shrug.
For a tight-fitting shrug, use a stretch fabric and take approximately 5 cm (2 inches) off measurement B before sewing.