Instructions

1

Determine how much shorter your existing pair of pants should be. To do so, put on the pants with the shoes you will normally be wearing with them, and have a friend help you measure where the hem should fall. You may want your hem to fall several inches above the bottom of a pair of sneakers, just at ground level or an inch or two above the bottom of a pair of heels, depending on the look you are going for. Make sure that the markings on each leg are the same distance from the bottom of the pants.
2

Roll the bottom of one pant leg up like a cuff. Make the cuff half the amount you would like to take off the pants, not including the existing hem. Pin the cuff in place, making sure that it is even all the way around and that the vertical seams match up exactly. Double-check your pinning with the measuring tape.
3

Place the end of the pant leg on your sewing machine so that you can stitch all the way around the leg. Line up the existing hem stitching with your needle, placing the needle slightly to the far side of the hem stitching. Use a heavy-duty needle to stitch just alongside the hem stitching, so that you can fold the excess material back later and still have the original hem attached to the bottom of the leg. Backstitch at the end of your line and clip the threads.
4

Put the pants on to make sure that you are satisfied with the length. If so, repeat Steps 2 to 3 on the other pant leg. If not, you will have to undo the stitching and start again.
5

Cut the excess rolled part of the pant legs to ½-inch short seam allowances; then iron these seam allowances open. Finish the seam allowances as you like, either by zigzag stitching, serging the raw edges or folding the seam allowances together and stitching them closed. You may prefer to clip the seam allowances shorter and serge the ends so that there is less bulk. Turn the pant legs right side out and press the old hem flat. You should now have pants in the appropriate length with the original hem still attached.