There are many ways to determine what size golf grip will best fit your hands. You can measure your hand, determine the grip size by the glove size you use or go by trial and error, gripping many different sizes to see which one feels best. Whatever method you choose, finding the right size can help your game. If your grip is too big, you will not get enough control over the club head and be unable to direct your golf ball correctly. If your grip is too small, you may overcorrect your wrist action and make the golf ball travel too far to the left or right. Ignoring this sizing issue can make the game harder than it should be.
Lay your hand palm up on a flat surface, preferably your glove hand since that is the one with the most surface area covering the grip.
Measure the length in inches from your wrist crease to the top of your middle finger.
Measure the length of the bottom of your middle finger to the tip.
Using a Golf Grips Direct sizing chart (see Resources), find the correct block for both measurements taken. The chart will tell you not only what grip you need but how many tape layers are needed to reach the perfect diameter for you. Tape layers can get you in between two grip sizes.
Put your golf glove on and make sure it is a proper fit. It should be comfortable but tight enough to be taut at the palm when the hand is outstretched.
Correlate the glove size with the grip size on Golf Pride's grip chart (see Resources).
Check the size by gripping the suggested grip on the chart. Since the chart shows two suggestions for each glove size, there may be need for extra tape layers.
Gather a sampling of all the different size grips. Most big golf retailers like Golfsmith and Golf Galaxy will showcase all their grips in their store for you to conduct this test. Grips must be assembled on a club shaft in order to experience the actual diameter of the grip. Holding a solo grip will not give you the accurate feeling of diameter.
Firmly grasp each grip with the left hand or glove hand. It is best if you have your glove on, as well.
Look for the middle finger to slightly touch the base of the thumb for an accurate fit. If the two cannot touch the grip is too big and if the two overlap the grip is too small.
Winn grips or leather grips have a different feel then rubber grips and may call for a grip size smaller. These grips cannot be manipulated by additional layers of tape under it. They are just to firm but they can be tested in trial and error without putting them on a club shaft.