Use a sewing machine to hem trousers as a quick alternative to the tedious task of hand-stitching a hem. While making small, nearly invisible stitches by hand offers the best results in hemming dress trousers, machine topstitching a straight line across the bottom of pant legs of jeans and casual wear such as khakis and cargo trousers creates acceptable, and even preferred, results.
Measure and Mark
Begin your hemming project by trying on your trousers while wearing shoes with the heel height you normally wear. Although pant length is a matter of personal preference, generally the back of the finished hem should fall about 1/2 inch or so above the heel of your shoes.
Turn up the bottom of the trousers to the desired length, folding the fabric to the inside of the pant leg. Adjust the amount of the fold until you are happy with the length. You’ll have to bend over to adjust the fold, but be sure to stand back up and check the look in a mirror before you make a decision. How the trousers fall when you are bending over will be different from how they fall when standing up straight. Also make sure the trousers rest comfortably around your waist area.
When satisfied with the length, pin the hem in place and take off the trousers. Rub tailor’s chalk along the bottom fold to make a line marking the finished length.
Cut and Sew
For straight-leg trousers, cut the fabric 3/4 of an inch below the chalk mark. Finish the raw edge by serging or zigzagging around the bottom. Using a free arm machine makes sewing pant legs easy.
Turn up the hem along the chalk line, press and re-pin the hem. With the right side of the trousers facing you, sew around the bottom edge, 1/2 inch up from the fold. For jeans, use thread especially made for denim to get the best look. For khakis or other casual trousers, use an all-purpose thread in a colour that most closely matches the fabric.
Flared trousers must be handled differently because the width of the pant leg changes as it progresses and will pucker when you turn up the hem. Sew one long edge of seam binding along the chalk-marked hem line, overlapping the narrow edges of the seam binding where the beginning and end come together. Cut off the excess pant fabric 1/4 inch away from the stitching line and then turn up the hem where the fabric and the seam binding meet. Sew the seam binding--which will “give” slightly because of the overlapped edges--to the pant leg.