Manufactured tennis racquet grip sizes range from less than 4" for juniors to 4 7/8" for the largest adult hands. This might not seem like much of a range, but the difference even 1/8" makes is surprising. Too large a grip can strain your hand, and prolonged use of too small a grip can injure your hand, wrist, and elbow.

The most commonly used method for finding your exact grip size is as follows: On your dominant hand, note that your palm has three main creases. Hold your hand flat, with the fingers alongside one another. Measure from the middle crease of your palm, up the line between your middle and ring fingers, to a point equal to the height of the tip of your ring finger. For the average woman, this measurement will fall between 4 1/8" and 4 3/8", for men between 4 1/2" and 4 3/4".