How To Know Racket Grip Size?

As a beginner tennis player, usually we will confuse on racket selection.Especially choosing of grip size of our racket.
The right grip size makes a huge difference in how a racquet performs.
Here simple way to measure our grip size:

Holding an eastern forehand grip (the palm is placed against the same bevel as the string face), you should be able to fit the index finger of your non-hitting hand in the space between your ring finger and palm. If there isn't enough room for your index finger, the grip is too small. If there is space between your finger and palm, the grip is too big. A too-small grip requires more muscle strength to keep the racquet from twisting in your hand. Prolonged use of a grip that's too small can contribute to tennis elbow problems. A grip that's too large inhibits wrist snap on serves, makes changing grips more difficult and also requires more muscle strength. Prolonged use of a grip that's too big can also contribute to tennis elbow problems.

European grip sizing is different than the US and is the source of some confusion. The chart below correlates US and European grip sizes.

US	Europe
4-1/8	1
4-1/4	2
4-3/8	3
4-1/2	4
4-5/8	5
4-3/4	6

As you can see, each European size corresponds to 1/8 inch (1=4-1/8, 2=4-2/8 or 1/4, etc.). So, increasing your grip by 1 size would equal 1/8 inch, whether using the US or European sizing system.