Summarize:

If your jump rope is too long, you will need to adjust the length. There are a couple of different ways to adjust the length of your jump rope. The easiest way to adjust your jump rope’s size is by tying a knot or a couple of knots in the rope. Tie the knot as close to the handle as you can without letting the knot actually touch the handle. If you need more than one knot to adjust the size, tie one knot (or two) on each side of the rope. This method is best for beaded and cloth ropes. Make sure that you have enough space to jump rope and that you can see the topmost part of your jump rope as it swings over your head.  If you can jump rope in front of a large mirror, that is ideal. If not, ask a friend to watch you.  As you jump rope, notice the distance between the top of your head and the middle of your rope.  For beginner jumpers, this distance should be about 16-30 inches.   For fitness jumpers, this distance should be about 6-10 inches.   For speed jumpers, this distance should be about 2-6 inches. Speed and control If your jump rope seems too long or too short, you can always readjust it by adding or taking out one of the knots that you made.
Adjust the length of your rope. Test your rope size. Readjust your jump rope as needed.