Many people who are interested in grip soon become aware of the size of their hands. The proper way to measure your hand is from the crease in your wrist closest to your palm, all the way to the tip of your middle finger.
The average guy has hands starting at 7" and going to 7 3/4". 8"+ is a big hand and 9"+ is a HUGE hand.
Way too many people put emphasis on hand size. If you have bigger hands, you'll do better when you start out in grip. It's like height in a strongman competition, it's very useful to be tall, but only one factor in a million. There are guys like the 6'7" former World's Strongest Man champ Magnus Samuelsson, closing #4's and there are guys like sub-6ft Tommy Heslep closing #4's.
In the future, US Grip hopes to introduce Hand Size divisions, similar to weight classes, into it's contests. Since height and weight mean little in Grip Strength, Hand size is the only logical division of classes. Right now, there simply aren't enough competitors to separate them into hand size classes. SO GET OUT THERE AND COMPETE!!!