Understanding the weight-to-length ratio is important to know when choosing the right bat. Simply subtract the number of ounces from the length inches to get your ratio. A -3 ratio is the size that must be used in high school, college, and adult league games. Another important thing to remember is that as of January 2012, all high school and college bats must have the new BBCOR stamp on it. To find out more on what to look for when purchasing your next bat, look at our bat buying guide.